Nanomaterials

20 pages, 9789 KiB

Open AccessArticle

Catalytic Reduction of p-Nitrophenol on MnO₂/Zeolite -13X Prepared with Lawsonia inermis Extract as a Stabilizing and Capping Agent

by Enshirah Da’na, Amel Taha and Mohamed R. El-Aassar

Nanomaterials 2023, 13(4), 785; https://doi.org/10.3390/nano13040785 - 20 Feb 2023

Cited by 10 | Viewed by 2324

Abstract

p-nitrophenol (pNP) is a highly toxic organic compound and is considered carcinogenic and mutagenic. It is a very stable compound with high resistance to chemical or biological degradation. As a result, the elimination of this pollutant has been very challenging for many researchers. [...] Read more.

p-nitrophenol (pNP) is a highly toxic organic compound and is considered carcinogenic and mutagenic. It is a very stable compound with high resistance to chemical or biological degradation. As a result, the elimination of this pollutant has been very challenging for many researchers. Catalytic reduction is one of the most promising techniques, if a suitable catalyst is developed. Thus, this work aims to prepare an eco-friendly catalyst via a simple and low-cost route and apply it for the conversion of the toxic p-nitrophenol (pNP) into a non-toxic p-aminophenol (pAP) that is widely used in industry. Manganese oxide was prepared in an environmentally friendly manner with the aid of Lawsonia inermis (henna) extract as a stabilizing and capping agent and loaded on the surface of 13X molecular sieve zeolite. The UV-Vis spectrum, EDS, and XRD patterns confirmed the formation of the pure MnO₂ loaded on the zeolite crystalline network. The TGA analysis showed that the samples prepared by loading MnO₂ on zeolite (Mn2Z, Mn3Z, and Mn4Z) lost more mass than pure MnO₂ (Mn) or zeolite (Z), which is mainly moisture adsorbed on the surface. This indicates a better dispersion of MnO₂ on the surface of zeolite compared to pure MnO₂, and thus a higher number of active adsorption sites. SEM images and EDS confirmed the dispersion of the MnO₂ on the surface of the zeolite. Results showed a very fast reduction rate, following the order Mn2Z > Mn3Z > Mn4Z > Mn > Z. With sample Mn2Z, 96% reduction of pNP was achieved in 9 min and 100% in 30 min. For Mn3Z, Mn4Z, and Mn, 98% reduction was achieved in 20 min and 100% in 30 min. Zeolite was the slowest, with only a 40% reduction in 30 min. Increasing the amount of zeolite in the synthesis mixture resulted in lower reduction efficiency. The kinetic study indicated that the reduction of p-nitrophenol on the surface of the prepared nanocomposite follows the pseudo-first-order model. The results show that the proposed nanocomposite is very effective and very promising to be commercially applied in water treatment, due to its low cost, simple synthesis procedure, and reusability. Full article

(This article belongs to the Special Issue Synthesis, Properties and Applications of Metal-Based Nanomaterials)

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9 pages, 2902 KiB

Open AccessCommunication

Epitaxial Lateral Overgrowth of GaN on a Laser-Patterned Graphene Mask

by Arūnas Kadys, Jūras Mickevičius, Kazimieras Badokas, Simonas Strumskis, Egidijus Vanagas, Žydrūnas Podlipskas, Ilja Ignatjev and Tadas Malinauskas

Nanomaterials 2023, 13(4), 784; https://doi.org/10.3390/nano13040784 - 20 Feb 2023

Cited by 2 | Viewed by 2381

Abstract

Epitaxial lateral overgrowth (ELO) of GaN epilayers on a sapphire substrate was studied by using a laser-patterned graphene interlayer. Monolayer graphene was transferred onto the sapphire substrate using a wet transfer technique, and its quality was confirmed by Raman spectroscopy. The graphene layer [...] Read more.

Epitaxial lateral overgrowth (ELO) of GaN epilayers on a sapphire substrate was studied by using a laser-patterned graphene interlayer. Monolayer graphene was transferred onto the sapphire substrate using a wet transfer technique, and its quality was confirmed by Raman spectroscopy. The graphene layer was ablated using a femtosecond laser, which produced well-defined patterns without damaging the underlying sapphire substrate. Different types of patterns were produced for ELO of GaN epilayers: stripe patterns were ablated along the

{[\bar{1} 100]}_{sapphire}

and

{[11 \bar{2} 0]}_{sapphire}

directions, a square island pattern was ablated additionally. The impact of the graphene pattern on GaN nucleation was analyzed by scanning electron microscopy. The structural quality of GaN epilayers was studied by cathodoluminescence. The investigation shows that the laser-ablated graphene can be integrated into the III-nitride growth process to improve crystal quality. Full article

(This article belongs to the Special Issue Graphene and Related 2D Materials)

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20 pages, 1732 KiB

Open AccessReview

Noble Metals Functionalized on Graphene Oxide Obtained by Different Methods—New Catalytic Materials

by Mihaela Iordache, Anisoara Oubraham, Ioan-Sorin Sorlei, Florin Alexandru Lungu, Catalin Capris, Tudor Popescu and Adriana Marinoiu

Nanomaterials 2023, 13(4), 783; https://doi.org/10.3390/nano13040783 - 20 Feb 2023

Cited by 13 | Viewed by 3067

Abstract

In recent years, research has focused on developing materials exhibiting outstanding mechanical, electrical, thermal, catalytic, magnetic and optical properties such as graphene/polymer, graphene/metal nanoparticles and graphene/ceramic nanocomposites. Two-dimensional sp² hybridized graphene has become a material of choice in research due to the [...] Read more.

In recent years, research has focused on developing materials exhibiting outstanding mechanical, electrical, thermal, catalytic, magnetic and optical properties such as graphene/polymer, graphene/metal nanoparticles and graphene/ceramic nanocomposites. Two-dimensional sp² hybridized graphene has become a material of choice in research due to the excellent properties it displays electrically, thermally, optically and mechanically. Noble nanomaterials also present special physical and chemical properties and, therefore, they provide model building blocks in modifying nanoscale structures for various applications, ranging from nanomedicine to catalysis and optics. The introduction of noble metal nanoparticles (NPs) (Au, Ag and Pd) into chemically derived graphene is important in opening new avenues for both materials in different fields where they can provide hybrid materials with exceptional performance due to the synergistical result of the specific properties of each of the materials. This review presents the different synthetic procedures for preparing Pt, Ag, Pd and Au NP/graphene oxide (GO) and reduced graphene oxide (rGO) composites. Full article

(This article belongs to the Special Issue Nanomaterials for Chemical Engineering (Volume II))

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15 pages, 4240 KiB

Open AccessArticle

Novel Electrically Conductive Cellulose Nanocrystals with a Core-Shell Nanostructure Towards Biodegradable Electronics

by Hatem Abushammala and Jia Mao

Nanomaterials 2023, 13(4), 782; https://doi.org/10.3390/nano13040782 - 20 Feb 2023

Cited by 1 | Viewed by 2167

Abstract

Electronic waste (e-waste) is the fastest growing waste stream and its negative impact on the environment and human health is major because of the toxicity and non-biodegradability of its constituents. For their biodegradability and nontoxicity, bio-based materials have been proposed as potential material [...] Read more.

Electronic waste (e-waste) is the fastest growing waste stream and its negative impact on the environment and human health is major because of the toxicity and non-biodegradability of its constituents. For their biodegradability and nontoxicity, bio-based materials have been proposed as potential material candidates in the field of electronics. Among these, cellulose nanocrystals (CNCs) have many interesting properties including biodegradability, high mechanical strength, and possibility to functionalize. In terms of electrical properties, CNCs are electrically insulated, limiting their potential in electronics. This work aims to build up a poly(o-toluidine)-like shell around the CNCs to render them conductive. For this goal, the surface of the CNCs was carbamated using 2,4-toluene diisocyanate through the para-isocyanates and the ortho-isocyanates were later hydrolyzed to amine groups using HCl-acidified dimethylsulfoxide. The resultant o-toluidine-like molecules on the CNC surface were then polymerized using ammonium persulfate to form an electrically conductive shell around each CNC. The resultant CNCs were then characterized for their chemical, morphological, and electrical properties. Fourier-transform infrared analysis of the CNCs at each stage confirmed the expected chemical changes upon carbamation, hydrolysis, and polymerization and X-ray diffraction confirmed the permanence of the native crystalline structure of the CNCs. The atomic force microscopy images showed that the obtained CNCs were on average slightly thicker than the original ones, possibly due to the growth of the poly(o-toluidine) shell around them. Finally, using the four-point method, the obtained CNCs were electrically conductive with a conductivity of 0.46 S/cm. Such novel electrically conductive CNCs should have great potential in a wide range of applications including electronics, sensing, and medicine. Full article

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14 pages, 5843 KiB

Open AccessArticle

Thermoelectric Power Generation of TiS₂/Organic Hybrid Superlattices Below Room Temperature

by Numan Salah, Neazar Baghdadi, Shittu Abdullahi, Ahmed Alshahrie and Kunihito Koumoto

Nanomaterials 2023, 13(4), 781; https://doi.org/10.3390/nano13040781 - 20 Feb 2023

Cited by 3 | Viewed by 1807

Abstract

Recently, the n-type TiS₂/organic hybrid superlattice (TOS) was found to have efficient thermoelectric (TE) properties above and near room temperature (RT). However, its TE performance and power generation at the temperature gradient below RT have not yet been reported. In this [...] Read more.

Recently, the n-type TiS₂/organic hybrid superlattice (TOS) was found to have efficient thermoelectric (TE) properties above and near room temperature (RT). However, its TE performance and power generation at the temperature gradient below RT have not yet been reported. In this work, the TE performance and power generation of the TOS above and below RT were investigated. The electrical conductivity (σ) and Seebeck coefficient (S) were recorded as a function of temperature within the range 233–323 K. The generated power at temperature gradients above (at ΔT = 20 and 40 K) and below (at ΔT = −20 and −40 K) RT was measured. The recorded σ decreased by heating the TOS, while |S| increased. The resulting power factor recorded ~100 µW/mK² at T = 233 K with a slight increase following heating. The charge carrier density and Hall mobility of the TOS showed opposite trends. The first factor significantly decreased after heating, while the second one increased. The TE-generated power of a single small module made of the TOS at ΔT = 20 and 40 K recorded 10 and 45 nW, respectively. Surprisingly, the generated power below RT is several times higher than that generated above RT. It reached 140 and 350 nW at ΔT = −20 and −40 K, respectively. These remarkable results indicate that TOS might be appropriate for generating TE power in cold environments below RT. Similar TE performances were recorded from both TOS films deposited on solid glass and flexible polymer, indicating TOS pertinence for flexible TE devices. Full article

(This article belongs to the Special Issue Advanced Nanoscale Materials for Thermoelectric Applications)

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17 pages, 2941 KiB

Open AccessReview

Emerging Two-Dimensional Materials-Based Electrochemical Sensors for Human Health and Environment Applications

by Muhammad Atif Khan, Faizan Ramzan, Muhammad Ali, Muhammad Zubair, Muhammad Qasim Mehmood and Yehia Massoud

Nanomaterials 2023, 13(4), 780; https://doi.org/10.3390/nano13040780 - 20 Feb 2023

Cited by 11 | Viewed by 2914

Abstract

Two-dimensional materials (2DMs) have been vastly studied for various electrochemical sensors. Among these, the sensors that are directly related to human life and health are extremely important. Owing to their exclusive properties, 2DMs are vastly studied for electrochemical sensing. Here we have provided [...] Read more.

Two-dimensional materials (2DMs) have been vastly studied for various electrochemical sensors. Among these, the sensors that are directly related to human life and health are extremely important. Owing to their exclusive properties, 2DMs are vastly studied for electrochemical sensing. Here we have provided a selective overview of 2DMs-based electrochemical sensors that directly affect human life and health. We have explored graphene and its derivatives, transition metal dichalcogenide and MXenes-based electrochemical sensors for applications such as glucose detection in human blood, detection of nitrates and nitrites, and sensing of pesticides. We believe that the areas discussed here are extremely important and we have summarized the prominent reports on these significant areas together. We believe that our work will be able to provide guidelines for the evolution of electrochemical sensors in the future. Full article

(This article belongs to the Special Issue Nanomaterials-Based Electrochemical (Bio)Sensors: Design, Fabrication, and Applications)

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21 pages, 6898 KiB

Open AccessArticle

Pore Structure and Gas Content Characteristics of Lower Jurassic Continental Shale Reservoirs in Northeast Sichuan, China

by Tao Jiang, Zhijun Jin, Hengyuan Qiu, Xuanhua Chen, Yuanhao Zhang and Zhanfei Su

Nanomaterials 2023, 13(4), 779; https://doi.org/10.3390/nano13040779 - 20 Feb 2023

Cited by 4 | Viewed by 1802

Abstract

The Jurassic shale in the northeastern Sichuan Basin is one of the main target intervals for continental shale gas exploitation. Research on the pore structure and gas-bearing properties of shales is the key issue in target interval optimization. Through core observation, geochemistry, bulk [...] Read more.

The Jurassic shale in the northeastern Sichuan Basin is one of the main target intervals for continental shale gas exploitation. Research on the pore structure and gas-bearing properties of shales is the key issue in target interval optimization. Through core observation, geochemistry, bulk minerals, scanning electron microscopy, nitrogen adsorption, and isothermal adsorption experiments, various lithofacies with different pore structure characteristics were clarified. In addition, the factors that control gas-bearing properties were discussed, and a continental shale gas enrichment model was finally established. The results show that the Jurassic continental shale in the northeastern Sichuan Basin can be classified into six lithofacies. Organic pores, intergranular pores, interlayer pores in clay minerals, intercrystalline pores in pyrite framboids, and dissolution pores can be observed in shale samples. Pore structures varied in different shale lithofacies. The contact angle of shales is commonly less than 45°, leading to complex wettability of pores in the shales. Free gas content is mainly controlled by the organic matter (OM) content and the brittleness in the Jurassic shale. The adsorbed gas content is mainly controlled by the OM content, clay mineral type, and water saturation of the shales. The enrichment mode of the Lower Jurassic continental shale gas in the northeastern Sichuan Basin is established. Paleoenvironments control the formation of organic-rich shales in the center part of lakes. The “baffle” layer helps the confinement and high pressure, and the complex syncline controls the preservation, forming the enrichment pattern of the complex syncline-central baffle layer. Full article

(This article belongs to the Special Issue Latest Advances and Prospects in Nanogeoscience)

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17 pages, 5514 KiB

Open AccessFeature PaperArticle

Synthesis of 3D Porous Cu Nanostructures on Ag Thin Film Using Dynamic Hydrogen Bubble Template for Electrochemical Conversion of CO₂ to Ethanol

by Farnood Rahmati, Negar Sabouhanian, Jacek Lipkowski and Aicheng Chen

Nanomaterials 2023, 13(4), 778; https://doi.org/10.3390/nano13040778 - 20 Feb 2023

Cited by 2 | Viewed by 2168

Abstract

Cu-based nanomaterials have been widely considered to be promising electrocatalysts for the direct conversion of CO₂ to high-value hydrocarbons. However, poor selectivity and slow kinetics have hindered the use of Cu-based catalysts for large-scale industrial applications. In this work, we report on [...] Read more.

Cu-based nanomaterials have been widely considered to be promising electrocatalysts for the direct conversion of CO₂ to high-value hydrocarbons. However, poor selectivity and slow kinetics have hindered the use of Cu-based catalysts for large-scale industrial applications. In this work, we report on a tunable Cu-based synthesis strategy using a dynamic hydrogen bubble template (DHBT) coupled with a sputtered Ag thin film for the electrochemical reduction of CO₂ to ethanol. Remarkably, the introduction of Ag into the base of the three-dimensional (3D) Cu nanostructure induced changes in the CO₂ reduction reaction (CO2RR) pathway, which resulted in the generation of ethanol with high Faradaic Efficiency (FE). This observation was further investigated through Tafel and electrochemical impedance spectroscopic analyses. The rational design of the electrocatalyst was shown to promote the spillover of formed CO intermediates from the Ag sites to the 3D porous Cu nanostructure for further reduction to C₂ products. Finally, challenges toward the development of multi-metallic electrocatalysts for the direct catalysis of CO₂ to hydrocarbons were elucidated, and future perspectives were highlighted. Full article

(This article belongs to the Special Issue Nanomaterials in Catalysis for Environmental and Energy Applications)

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12 pages, 3726 KiB

Open AccessArticle

Porous Nb₂O₅ Formed by Anodic Oxidation as the Sulfur Host for Enhanced Performance Lithium-Sulfur Batteries

by Jianming Wang, Lu Chen, Bo Zhao, Chunyong Liang, Hongshui Wang and Yongguang Zhang

Nanomaterials 2023, 13(4), 777; https://doi.org/10.3390/nano13040777 - 20 Feb 2023

Cited by 1 | Viewed by 2034

Abstract

Lithium-sulfur batteries (LSBs), with their high theoretical specific capacity and energy density, have great potential to be a candidate for secondary batteries in the future. However, Li-S batteries suffer from multiple issues and challenges, for example, uneven growth of lithium dendrites, low utilization [...] Read more.

Lithium-sulfur batteries (LSBs), with their high theoretical specific capacity and energy density, have great potential to be a candidate for secondary batteries in the future. However, Li-S batteries suffer from multiple issues and challenges, for example, uneven growth of lithium dendrites, low utilization of the active material (sulfur), and low specific capacity. This paper reports a low-cost and anodic oxidation method to produce niobium pentoxide with a porous structure (P-Nb₂O₅). A simple one-step process was used to synthesize P-Nb₂O₅ with porous structures by anodizing niobium at 40 V in fluorinated glycerol. The porous Nb₂O₅ showed excellent rate capability and good capacity retention by maintaining its structural integrity, allowing us to determine the advantages of its porous structure. As a result of the highly porous structure, the sulfur was not only provided with adequate storage space and abundant adsorption points, but it was also utilized more effectively. The initial discharge capacity with the P-Nb₂O₅ cathode rose to 1106.8 mAh·g⁻¹ and dropped to 810.7 mAh·g⁻¹ after 100 cycles, which demonstrated the good cycling performance of the battery. This work demonstrated that the P-Nb₂O₅ prepared by the oxidation method has strong adsorption properties and good chemical affinity. Full article

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12 pages, 49668 KiB

Open AccessArticle

Structural Construction of WO₃ Nanorods as Anode Materials for Lithium-Ion Batteries to Improve Their Electrochemical Performance

by Yunpeng Zhang, Keke Zhu, Rui Li, Suyuan Zeng and Lei Wang

Nanomaterials 2023, 13(4), 776; https://doi.org/10.3390/nano13040776 - 20 Feb 2023

Cited by 3 | Viewed by 2123

Abstract

WO₃ nanobundles and nanorods were prepared using a facile hydrothermal method. The X-ray diffraction pattern confirms that the obtained samples are pure hexagonal WO₃. Transmission electron microscope images detected the gap between the different nanowires that made up the nanobundles [...] Read more.

WO₃ nanobundles and nanorods were prepared using a facile hydrothermal method. The X-ray diffraction pattern confirms that the obtained samples are pure hexagonal WO₃. Transmission electron microscope images detected the gap between the different nanowires that made up the nanobundles and nanorods. As the anode materials of lithium-ion batteries, the formed WO₃ nanobundles and WO₃ nanorods deliver an initial discharge capacity of 883.5 and 971.6 mA h g⁻¹, respectively. Both WO₃ nanostructures deliver excellent capacity retention upon extended cycling. At a current density of 500 mA g⁻¹, the reversible capacities of WO₃ nanobundle and WO₃ nanorod electrodes are 444.0 and 472.3 mA h g⁻¹, respectively, after 60 cycles. Full article

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16 pages, 3237 KiB

Open AccessArticle

Comparative Study of α- and β-MnO₂ on Methyl Mercaptan Decomposition: The Role of Oxygen Vacancies

by Hong Su, Jiangping Liu, Yanan Hu, Tianhao Ai, Chenhao Gong, Jichang Lu and Yongming Luo

Nanomaterials 2023, 13(4), 775; https://doi.org/10.3390/nano13040775 - 19 Feb 2023

Cited by 5 | Viewed by 2540

Abstract

As a representative sulfur-containing volatile organic compounds (S-VOCs), CH₃SH has attracted widespread attention due to its adverse environmental and health risks. The performance of Mn-based catalysts and the effect of their crystal structure on the CH₃SH catalytic reaction have [...] Read more.

As a representative sulfur-containing volatile organic compounds (S-VOCs), CH₃SH has attracted widespread attention due to its adverse environmental and health risks. The performance of Mn-based catalysts and the effect of their crystal structure on the CH₃SH catalytic reaction have yet to be systematically investigated. In this paper, two different crystalline phases of tunneled MnO₂ (α-MnO₂ and β-MnO₂) with the similar nanorod morphology were used to remove CH₃SH, and their physicochemical properties were comprehensively studied using high-resolution transmission electron microscope (HRTEM) and electron paramagnetic resonance (EPR), H₂-TPR, O₂-TPD, Raman, and X-ray photoelectron spectroscopy (XPS) analysis. For the first time, we report that the specific reaction rate for α-MnO₂ (0.029 mol g⁻¹ h⁻¹) was approximately 4.1 times higher than that of β-MnO₂ (0.007 mol g⁻¹ h⁻¹). The as-synthesized α-MnO₂ exhibited higher CH₃SH catalytic activity towards CH₃SH than that of β-MnO₂, which can be ascribed to the additional oxygen vacancies, stronger surface oxygen migration ability, and better redox properties from α-MnO₂. The oxygen vacancies on the catalyst surface provided the main active sites for the chemisorption of CH₃SH, and the subsequent electron transfer led to the decomposition of CH₃SH. The lattice oxygen on catalysts could be released during the reaction and thus participated in the further oxidation of sulfur-containing species. CH₃SSCH₃, S⁰, SO₃²⁻, and SO₄²⁻ were identified as the main products of CH₃SH conversion. This work offers a new understanding of the interface interaction mechanism between Mn-based catalysts and S-VOCs. Full article

(This article belongs to the Special Issue Nanocatalysts for Air Purification)

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36 pages, 13694 KiB

Open AccessReview

Metallocene-Filled Single-Walled Carbon Nanotube Hybrids

by Marianna V. Kharlamova and Christian Kramberger

Nanomaterials 2023, 13(4), 774; https://doi.org/10.3390/nano13040774 - 19 Feb 2023

Cited by 7 | Viewed by 2937

Abstract

In this paper, the growth mechanism, structure, growth processes, growth kinetics, and optical, vibronic and electronic properties of metallocene-filled single-walled carbon nanotubes (SWCNTs) are considered. A description of the procedures used to fill the nanotubes is provided. An investigation of doping effects on [...] Read more.

In this paper, the growth mechanism, structure, growth processes, growth kinetics, and optical, vibronic and electronic properties of metallocene-filled single-walled carbon nanotubes (SWCNTs) are considered. A description of the procedures used to fill the nanotubes is provided. An investigation of doping effects on metallicity-mixed SWCNTs filled with metallocenes by Raman spectroscopy, near edge X-ray absorption fine structure spectroscopy, photoemission spectroscopy, and optical absorption spectroscopy is described. The studies of doping effects on metallicity-sorted SWCNTs filled with metallocenes are discussed. Doping effects in metallicity-mixed and sorted SWCNTs upon the chemical transformation of encapsulated molecules are analyzed. A discussion of the modification of the electronic properties of filled SWCNTs is presented. Applications of metallocene-filled SWCNTs in electrochemistry, thermoelectric power generation, chemical sensors, and magnetic recording are discussed. Full article

(This article belongs to the Special Issue Applications of Synthesis Methods for Preparation of Carbon Nanotubes and Related Nanomaterials)

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6 pages, 1327 KiB

Open AccessCommunication

Multifunctional Cu-Se Alloy Core Fibers and Micro–Nano Tapers

by Min Sun, Yu Liu, Dongdan Chen and Qi Qian

Nanomaterials 2023, 13(4), 773; https://doi.org/10.3390/nano13040773 - 19 Feb 2023

Cited by 2 | Viewed by 1447

Abstract

Cu-Se alloy core fibers with glass cladding were fabricated by a thermal drawing method of a reactive molten core. The composition, crystallography, and photoelectric/thermoelectric performance of the fiber cores were investigated. The X-ray diffraction spectra of the Cu-Se alloy core fibers illustrate the [...] Read more.

Cu-Se alloy core fibers with glass cladding were fabricated by a thermal drawing method of a reactive molten core. The composition, crystallography, and photoelectric/thermoelectric performance of the fiber cores were investigated. The X-ray diffraction spectra of the Cu-Se alloy core fibers illustrate the fiber cores being polycrystalline with CuSe and Cu₃Se₂ phases. Interestingly, the fiber cores show a lower electrical conductivity under laser irradiation than under darkness at room temperature. Meanwhile, the fiber cores possess a power factor of ~1.2 mWm⁻¹K⁻² at room temperature, which is approaching the value of the high thermoelectric performance bulk of Cu₂Se polycrystals. The flexible Cu-Se fibers and their micro–nano tapers have potential multifunctional applications in the field of photoelectric detection and thermoelectric conversion on curved surfaces. Full article

(This article belongs to the Special Issue Advanced Nanoscale Materials for Thermoelectric Applications)

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17 pages, 34147 KiB

Open AccessEditor’s ChoiceArticle

Bioactive Composite Methacrylated Gellan Gum for 3D-Printed Bone Tissue-Engineered Scaffolds

by Ugo D’Amora, Alfredo Ronca, Stefania Scialla, Alessandra Soriente, Paola Manini, Jun Wei Phua, Christoph Ottenheim, Alessandro Pezzella, Giovanna Calabrese, Maria Grazia Raucci and Luigi Ambrosio

Nanomaterials 2023, 13(4), 772; https://doi.org/10.3390/nano13040772 - 19 Feb 2023

Cited by 13 | Viewed by 2904

Abstract

Gellan gum (GG) was chemically modified with methacrylic moieties to produce a photocrosslinkable biomaterial ink, hereinafter called methacrylated GG (GGMA), with improved physico-chemical properties, mechanical behavior and stability under physiological conditions. Afterwards, GGMA was functionalized by incorporating two different bioactive compounds, a naturally [...] Read more.

Gellan gum (GG) was chemically modified with methacrylic moieties to produce a photocrosslinkable biomaterial ink, hereinafter called methacrylated GG (GGMA), with improved physico-chemical properties, mechanical behavior and stability under physiological conditions. Afterwards, GGMA was functionalized by incorporating two different bioactive compounds, a naturally derived eumelanin extracted from the black soldier fly (BSF-Eumel), or hydroxyapatite nanoparticles (HAp), synthesized by the sol–gel method. Different ink formulations based on GGMA (2 and 4% (w/v)), BSF-Eumel, at a selected concentration (0.3125 mg/mL), or HAp (10 and 30% w_HAp/w_GGMA) were developed and processed by three-dimensional (3D) printing. All the functionalized GGMA-based ink formulations allowed obtaining 3D-printed GGMA-based scaffolds with a well-organized structure. For both bioactive signals, the scaffolds with the highest GGMA concentration (4% (w/v)) and the highest percentage of infill (45%) showed the best performances in terms of morphological and mechanical properties. Indeed, these scaffolds showed a good structural integrity over 28 days. Given the presence of negatively charged groups along the eumelanin backbone, scaffolds consisting of GGMA/BSF-Eumel demonstrated a higher stability. From a mechanical point of view, GGMA/BSF-Eumel scaffolds exhibited values of storage modulus similar to those of GGMA ones, while the inclusion of HAp at 30% (w_HAp/w_GGMA) led to a storage modulus of 32.5 kPa, 3.5-fold greater than neat GGMA. In vitro studies proved the capability of the bioactivated 3D-printed scaffolds to support 7F2 osteoblast cell growth and differentiation. BSF-Eumel and HAp triggered a different time-dependent physiological response in the osteoblasts. Specifically, while the ink with BSF-Eumel acted as a stimulus towards cell proliferation, reaching the highest value at 14 days, a higher expression of alkaline phosphatase activity was detected for scaffolds consisting of GGMA and HAp. The overall findings demonstrated the possible use of these biomaterial inks for 3D-printed bone tissue-engineered scaffolds. Full article

(This article belongs to the Special Issue Micro- and Nanostructured Biomaterials for Biomedical Applications and Regenerative Medicine)

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16 pages, 3242 KiB

Open AccessEditor’s ChoiceArticle

Enhanced Magnetism and Anomalous Hall Transport through Two-Dimensional Tungsten Disulfide Interfaces

by Chang-Ming Hung, Diem Thi-Xuan Dang, Amit Chanda, Derick Detellem, Noha Alzahrani, Nalaka Kapuruge, Yen T. H. Pham, Mingzu Liu, Da Zhou, Humberto R. Gutierrez, Darío A. Arena, Mauricio Terrones, Sarath Witanachchi, Lilia M. Woods, Hariharan Srikanth and Manh-Huong Phan

Nanomaterials 2023, 13(4), 771; https://doi.org/10.3390/nano13040771 - 18 Feb 2023

Cited by 3 | Viewed by 2684

Abstract

The magnetic proximity effect (MPE) has recently been explored to manipulate interfacial properties of two-dimensional (2D) transition metal dichalcogenide (TMD)/ferromagnet heterostructures for use in spintronics and valleytronics. However, a full understanding of the MPE and its temperature and magnetic field evolution in these [...] Read more.

The magnetic proximity effect (MPE) has recently been explored to manipulate interfacial properties of two-dimensional (2D) transition metal dichalcogenide (TMD)/ferromagnet heterostructures for use in spintronics and valleytronics. However, a full understanding of the MPE and its temperature and magnetic field evolution in these systems is lacking. In this study, the MPE has been probed in Pt/WS₂/BPIO (biphase iron oxide, Fe₃O₄ and α-Fe₂O₃) heterostructures through a comprehensive investigation of their magnetic and transport properties using magnetometry, four-probe resistivity, and anomalous Hall effect (AHE) measurements. Density functional theory (DFT) calculations are performed to complement the experimental findings. We found that the presence of monolayer WS₂ flakes reduces the magnetization of BPIO and hence the total magnetization of Pt/WS₂/BPIO at T > ~120 K—the Verwey transition temperature of Fe₃O₄ (T_V). However, an enhanced magnetization is achieved at T < T_V. In the latter case, a comparative analysis of the transport properties of Pt/WS₂/BPIO and Pt/BPIO from AHE measurements reveals ferromagnetic coupling at the WS₂/BPIO interface. Our study forms the foundation for understanding MPE-mediated interfacial properties and paves a new pathway for designing 2D TMD/magnet heterostructures for applications in spintronics, opto-spincaloritronics, and valleytronics. Full article

(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)

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18 pages, 3753 KiB

Open AccessArticle

Lamivudine and Zidovudine-Loaded Nanostructures: Green Chemistry Preparation for Pediatric Oral Administration

by Marina D. V. Guedes, Morgana S. Marques, Simone J. Berlitz, Murilo H. M. Facure, Daniel S. Correa, Clarice Steffens, Renata V. Contri and Irene C. Külkamp-Guerreiro

Nanomaterials 2023, 13(4), 770; https://doi.org/10.3390/nano13040770 - 18 Feb 2023

Cited by 5 | Viewed by 2023

Abstract

Here, we report on the development of lipid-based nanostructures containing zidovudine (1 mg/mL) and lamivudine (0.5 mg/mL) for oral administration in the pediatric population, eliminating the use of organic solvents, which is in accordance with green chemistry principles. The formulations were obtained by [...] Read more.

Here, we report on the development of lipid-based nanostructures containing zidovudine (1 mg/mL) and lamivudine (0.5 mg/mL) for oral administration in the pediatric population, eliminating the use of organic solvents, which is in accordance with green chemistry principles. The formulations were obtained by ultrasonication using monoolein (MN) or phytantriol (PN), which presented narrow size distributions with similar mean particle sizes (~150 nm) determined by laser diffraction. The zeta potential and the pH values of the formulations were around −4.0 mV and 6.0, respectively. MN presented a slightly higher incorporation rate compared to PN. Nanoemulsions were obtained when using monoolein, while cubosomes were obtained when using phytantriol, as confirmed by Small-Angle X-ray Scattering. The formulations enabled drug release control and protection against acid degradation. The drug incorporation was effective and the analyses using an electronic tongue indicated a difference in palatability between the nanotechnological samples in comparison with the drug solutions. In conclusion, PN was considered to have the strongest potential as a novel oral formulation for pediatric HIV treatment. Full article

(This article belongs to the Special Issue Nanomaterials in Biomedicine)

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15 pages, 3255 KiB

Open AccessArticle

MoS₂ Nanoplatelets on Hybrid Core-Shell (HyCoS) AuPd NPs for Hybrid SERS Platform for Detection of R6G

by Shusen Lin, Rutuja Mandavkar, Shalmali Burse, Md Ahasan Habib, Tasmia Khalid, Mehedi Hasan Joni, Young-Uk Chung, Sundar Kunwar and Jihoon Lee

Nanomaterials 2023, 13(4), 769; https://doi.org/10.3390/nano13040769 - 18 Feb 2023

Cited by 4 | Viewed by 2490

Abstract

In this work, a novel hybrid SERS platform incorporating hybrid core-shell (HyCoS) AuPd nanoparticles (NPs) and MoS₂ nanoplatelets has been successfully demonstrated for strong surface-enhanced Raman spectroscopy (SERS) enhancement of Rhodamine 6G (R6G). A significantly improved SERS signal of R6G is observed [...] Read more.

In this work, a novel hybrid SERS platform incorporating hybrid core-shell (HyCoS) AuPd nanoparticles (NPs) and MoS₂ nanoplatelets has been successfully demonstrated for strong surface-enhanced Raman spectroscopy (SERS) enhancement of Rhodamine 6G (R6G). A significantly improved SERS signal of R6G is observed on the hybrid SERS platform by adapting both electromagnetic mechanism (EM) and chemical mechanism (CM) in a single platform. The EM enhancement originates from the unique plasmonic HyCoS AuPd NP template fabricated by the modified droplet epitaxy, which exhibits strong plasmon excitation of hotspots at the nanogaps of metallic NPs and abundant generation of electric fields by localized surface plasmon resonance (LSPR). Superior LSPR results from the coupling of distinctive AuPd core-shell NP and high-density background Au NPs. The CM enhancement is associated with the charge transfer from the MoS₂ nanoplatelets to the R6G. The direct contact via mixing approach with optimal mixing ratio can effectively facilitate the charges transfer to the HOMO and LUMO of R6G, leading to the orders of Raman signal amplification. The enhancement factor (EF) for the proposed hybrid platform reaches ~10¹⁰ for R6G on the hybrid SERS platform. Full article

(This article belongs to the Special Issue Quantum Nanostructures by Droplet Epitaxy for Optoelectronics and Quantum Information Technologies II)

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10 pages, 2006 KiB

Open AccessArticle

Demonstration of a Learning-Empowered Fiber Specklegram Sensor Based on Focused Ion Beam Milling for Refractive Index Sensing

by Liangliang Gu, Han Gao and Haifeng Hu

Nanomaterials 2023, 13(4), 768; https://doi.org/10.3390/nano13040768 - 18 Feb 2023

Cited by 5 | Viewed by 1856

Abstract

We report a simple and robust fiber specklegram refractive index sensor with a multimode fiber-single mode fiber-multimode fiber structure based on focused ion beam milling. In this work, a series of fluid channels are etched on the single-mode fiber by using focused ion [...] Read more.

We report a simple and robust fiber specklegram refractive index sensor with a multimode fiber-single mode fiber-multimode fiber structure based on focused ion beam milling. In this work, a series of fluid channels are etched on the single-mode fiber by using focused ion beam milling to enhance the interaction between light and matter, and a deep learning model is employed to demodulate the sensing signal according to the speckle patterns collected from the output end of the multimode fiber. The feasibility and effectiveness of the proposed scheme were verified by rigorous experiments, and the test results showed that the demodulation accuracy and speed could reach 99.68% and 4.5 ms per frame, respectively, for the refractive index range of 1.3326 to 1.3679. The proposed sensing scheme has the advantages of low cost, easy implementation, and a simple measurement system, and it is expected to find applications in various chemical and biological sensing. Full article

(This article belongs to the Special Issue Advanced Semiconductor Nanomaterials for Electronic and Optoelectronic Applications)

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16 pages, 1239 KiB

Open AccessFeature PaperArticle

Titanium Dioxide Nanoparticles Modulate Systemic Immune Response and Increase Levels of Reduced Glutathione in Mice after Seven-Week Inhalation

by Miroslava Lehotska Mikusova, Milena Busova, Jana Tulinska, Vlasta Masanova, Aurelia Liskova, Iveta Uhnakova, Maria Dusinska, Zora Krivosikova, Eva Rollerova, Radka Alacova, Ladislava Wsolova, Mira Horvathova, Michaela Szabova, Norbert Lukan, Zbynek Vecera, Pavel Coufalik, Kamil Krumal, Lukas Alexa, Vojtech Thon, Pavel Piler, Marcela Buchtova, Lucie Vrlikova, Pavel Moravec, Dusan Galanda and Pavel Mikuska Show full author list Hide full author list

Nanomaterials 2023, 13(4), 767; https://doi.org/10.3390/nano13040767 - 18 Feb 2023

Cited by 8 | Viewed by 3203

Abstract

Titanium dioxide nanoparticles (TiO₂ NPs) are used in a wide range of applications. Although inhalation of NPs is one of the most important toxicologically relevant routes, experimental studies on potential harmful effects of TiO₂ NPs using a whole-body inhalation chamber model [...] Read more.

Titanium dioxide nanoparticles (TiO₂ NPs) are used in a wide range of applications. Although inhalation of NPs is one of the most important toxicologically relevant routes, experimental studies on potential harmful effects of TiO₂ NPs using a whole-body inhalation chamber model are rare. In this study, the profile of lymphocyte markers, functional immunoassays, and antioxidant defense markers were analyzed to evaluate the potential adverse effects of seven-week inhalation exposure to two different concentrations of TiO₂ NPs (0.00167 and 0.1308 mg TiO₂/m³) in mice. A dose-dependent effect of TiO₂ NPs on innate immunity was evident in the form of stimulated phagocytic activity of monocytes in low-dose mice and suppressed secretory function of monocytes (IL-18) in high-dose animals. The effect of TiO₂ NPs on adaptive immunity, manifested in the spleen by a decrease in the percentage of T-cells, a reduction in T-helper cells, and a dose-dependent decrease in lymphocyte cytokine production, may indicate immunosuppression in exposed mice. The dose-dependent increase in GSH concentration and GSH/GSSG ratio in whole blood demonstrated stimulated antioxidant defense against oxidative stress induced by TiO₂ NP exposure. Full article

(This article belongs to the Special Issue In Vivo Toxicological Evaluation of Metal Nanoparticles)

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13 pages, 3376 KiB

Open AccessArticle

Investigation of a Multi-Layer Absorber Exhibiting the Broadband and High Absorptivity in Red Light and Near-Infrared Region

by Guoxiang Peng, Wei-Zheng Li, Ling-Chieh Tseng and Cheng-Fu Yang

Nanomaterials 2023, 13(4), 766; https://doi.org/10.3390/nano13040766 - 18 Feb 2023

Cited by 9 | Viewed by 1713

Abstract

In this study, an absorber with the characteristics of high absorptivity and ultra-wideband (UWB), which was ranged from the visible light range and near-infrared band, was designed and numerically analyzed using COMSOL Multiphysics^® simulation software (version 6.0). The designed absorber was constructed [...] Read more.

In this study, an absorber with the characteristics of high absorptivity and ultra-wideband (UWB), which was ranged from the visible light range and near-infrared band, was designed and numerically analyzed using COMSOL Multiphysics^® simulation software (version 6.0). The designed absorber was constructed by using two-layer square cubes stacked on the four-layer continuous plane films. The two-layer square cubes were titanium dioxide (TiO₂) and titanium (Ti) (from top to bottom) and the four-layer continuous plane films were Poly(N-isopropylacrylamide) (PNIPAAm), Ti, silica (SiO₂), and Ti. The analysis results showed that the first reason to cause the high absorptivity in UWB is the anti-reflection effect of top TiO₂ layer. The second reason is that the three different resonances, including localized surface plasmon resonance, the propagating surface plasmon resonance, and the Fabry-Perot (FP) cavity resonance, are coexisted in the absorption peaks of the designed absorber and at least two of them can be excited at the same time. The third reason is that two FP resonant cavities were formed in the PNIPAAm and SiO₂ dielectric layers. Because of the combination of the anti-reflection effect and the three different resonances, the designed absorber presented the properties of UWB and high absorptivity. Full article

(This article belongs to the Special Issue Excitons and Phonons in Two-Dimensional Materials: From Fundamental to Applications)

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19 pages, 3902 KiB

Open AccessReview

Sustainable Biomass-Derived Carbon Electrodes for Potassium and Aluminum Batteries: Conceptualizing the Key Parameters for Improved Performance

by Glaydson Simões Dos Reis, Shaikshavali Petnikota, Chandrasekar M. Subramaniyam, Helinando Pequeno de Oliveira, Sylvia Larsson, Mikael Thyrel, Ulla Lassi and Flaviano García Alvarado

Nanomaterials 2023, 13(4), 765; https://doi.org/10.3390/nano13040765 - 17 Feb 2023

Cited by 12 | Viewed by 3043

Abstract

The development of sustainable, safe, low-cost, high energy and density power-density energy storage devices is most needed to electrify our modern needs to reach a carbon-neutral society by ~2050. Batteries are the backbones of future sustainable energy sources for both stationary off-grid and [...] Read more.

The development of sustainable, safe, low-cost, high energy and density power-density energy storage devices is most needed to electrify our modern needs to reach a carbon-neutral society by ~2050. Batteries are the backbones of future sustainable energy sources for both stationary off-grid and mobile plug-in electric vehicle applications. Biomass-derived carbon materials are extensively researched as efficient and sustainable electrode/anode candidates for lithium/sodium-ion chemistries due to their well-developed tailored textures (closed pores and defects) and large microcrystalline interlayer spacing and therefore opens-up their potential applications in sustainable potassium and aluminum batteries. The main purpose of this perspective is to brief the use of biomass residues for the preparation of carbon electrodes for potassium and aluminum batteries annexed to the biomass-derived carbon physicochemical structures and their aligned electrochemical properties. In addition, we presented an outlook as well as some challenges faced in this promising area of research. We believe that this review enlightens the readers with useful insights and a reasonable understanding of issues and challenges faced in the preparation, physicochemical properties and application of biomass-derived carbon materials as anodes and cathode candidates for potassium and aluminum batteries, respectively. In addition, this review can further help material scientists to seek out novel electrode materials from different types of biomasses, which opens up new avenues in the fabrication/development of next-generation sustainable and high-energy density batteries. Full article

(This article belongs to the Special Issue Nanostructured and Functional Nanomaterials for Energy Storage and Removal of Pollutants)

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16 pages, 3976 KiB

Open AccessEditor’s ChoiceArticle

Environmentally Friendly Improvement of Plasmonic Nanostructure Functionality towards Magnetic Resonance Applications

by Miroslava Flimelová, Yury V. Ryabchikov, Jan Behrends and Nadezhda M. Bulgakova

Nanomaterials 2023, 13(4), 764; https://doi.org/10.3390/nano13040764 - 17 Feb 2023

Cited by 9 | Viewed by 2303

Abstract

Plasmonic nanostructures have attracted a broad research interest due to their application perspectives in various fields such as biosensing, catalysis, photovoltaics, and biomedicine. Their synthesis by pulsed laser ablation in pure water enables eliminating various side effects originating from chemical contamination. Another advantage [...] Read more.

Plasmonic nanostructures have attracted a broad research interest due to their application perspectives in various fields such as biosensing, catalysis, photovoltaics, and biomedicine. Their synthesis by pulsed laser ablation in pure water enables eliminating various side effects originating from chemical contamination. Another advantage of pulsed laser ablation in liquids (PLAL) is the possibility to controllably produce plasmonic nanoparticles (NPs) in combination with other plasmonic or magnetic materials, thus enhancing their functionality. However, the PLAL technique is still challenging in respect of merging metallic and semiconductor specific features in nanosized objects that could significantly broaden application areas of plasmonic nanostructures. In this work, we performed synthesis of hybrid AuSi NPs with novel modalities by ultrashort laser ablation of bulk gold in water containing silicon NPs. The Au/Si atomic ratio in the nanohybrids was finely varied from 0.5 to 3.5 when changing the initial Si NPs concentration in water from 70 µg/mL to 10 µg/mL, respectively, without requiring any complex chemical procedures. It has been found that the laser-fluence-insensitive silicon content depends on the mass of nanohybrids. A high concentration of paramagnetic defects (2.2·× 10¹⁸ spin/g) in polycrystalline plasmonic NPs has been achieved. Our findings can open further prospects for plasmonic nanostructures as contrast agents in optical and magnetic resonance imaging techniques, biosensing, and cancer theranostics. Full article

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12 pages, 6326 KiB

Open AccessArticle

Enhancement of the Surface Morphology of (Bi_0.4Sb_0.6)₂Te₃ Thin Films by In Situ Thermal Annealing

by Liesbeth Mulder, Hanne van de Glind, Alexander Brinkman and Omar Concepción

Nanomaterials 2023, 13(4), 763; https://doi.org/10.3390/nano13040763 - 17 Feb 2023

Cited by 2 | Viewed by 1658

Abstract

The study of the exotic properties of the surface states of topological insulators requires defect-free and smooth surfaces. This work aims to study the enhancement of the surface morphology of optimally doped, high-crystalline (Bi_0.4Sb_0.6)₂Te₃ films deposited [...] Read more.

The study of the exotic properties of the surface states of topological insulators requires defect-free and smooth surfaces. This work aims to study the enhancement of the surface morphology of optimally doped, high-crystalline (Bi_0.4Sb_0.6)₂Te₃ films deposited by molecular beam epitaxy on Al₂O₃ (001) substrates. Atomic force microscopy shows that by employing an in situ thermal post anneal, the surface roughness is reduced significantly, and transmission electron microscopy reveals that structural defects are diminished substantially. Thence, these films provide a great platform for the research on the thickness-dependent properties of topological insulators. Full article

(This article belongs to the Special Issue Advances in Topological Materials: Fundamentals, Challenges and Outlook, Volume II)

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14 pages, 2698 KiB

Open AccessArticle

Single-Step Synthesis of Graphitic Carbon Nitride Nanomaterials by Directly Calcining the Mixture of Urea and Thiourea: Application for Rhodamine B (RhB) Dye Degradation

by Agidew Sewnet, Esayas Alemayehu, Mulualem Abebe, Dhakshnamoorthy Mani, Sabu Thomas, Nandakumar Kalarikkal and Bernd Lennartz

Nanomaterials 2023, 13(4), 762; https://doi.org/10.3390/nano13040762 - 17 Feb 2023

Cited by 16 | Viewed by 5155

Abstract

Recently, polymeric graphitic carbon nitride (g-C₃N₄) has been explored as a potential catalytic material for the removal of organic pollutants in wastewater. In this work, graphitic carbon nitride (g-C₃N₄) photocatalysts were synthesized using mixtures of [...] Read more.

Recently, polymeric graphitic carbon nitride (g-C₃N₄) has been explored as a potential catalytic material for the removal of organic pollutants in wastewater. In this work, graphitic carbon nitride (g-C₃N₄) photocatalysts were synthesized using mixtures of low-cost, environment-friendly urea and thiourea as precursors by varying calcination temperatures ranging from 500 to 650 °C for 3 h in an air medium. Different analytical methods were used to characterize prepared g-C₃N₄ samples. The effects of different calcination temperatures on the structural, morphological, optical, and physiochemical properties of g-C₃N₄ photocatalysts were investigated. The results showed that rhodamine B (RhB) dye removal efficiency of g-C₃N₄ prepared at a calcination temperature of 600 °C exhibited 94.83% within 180 min visible LED light irradiation. Photocatalytic activity of g-C₃N₄ was enhanced by calcination at higher temperatures, possibly by increasing crystallinity that ameliorated the separation of photoinduced charge carriers. Thus, controlling the type of precursors and calcination temperatures has a great impact on the photocatalytic performance of g-C₃N₄ towards the photodegradation of RhB dye. This investigation provides useful information about the synthesis of novel polymeric g-C₃N₄ photocatalysts using a mixture of two different environmentally benign precursors at high calcination temperatures for the photodegradation of organic pollutants. Full article

(This article belongs to the Special Issue The Development of Nanomaterials in Adsorption, Separation and Purification)

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17 pages, 2678 KiB

Open AccessFeature PaperArticle

Magnetoelectric Coupling in Room Temperature Multiferroic Ba₂EuFeNb₄O₁₅/BaFe₁₂O₁₉ Epitaxial Heterostructures Grown by Laser Ablation

by Thameur Hajlaoui, Catalin Harnagea and Alain Pignolet

Nanomaterials 2023, 13(4), 761; https://doi.org/10.3390/nano13040761 - 17 Feb 2023

Cited by 1 | Viewed by 1852

Abstract

Multiferroic thin films are a promising class of multifunctional materials, since they allow the integration of multiple functionalities within a single device. In order to overcome the scarcity of single phase multiferroics, it is crucial to develop novel multiferroic heterostructures, combining good ferroelectric [...] Read more.

Multiferroic thin films are a promising class of multifunctional materials, since they allow the integration of multiple functionalities within a single device. In order to overcome the scarcity of single phase multiferroics, it is crucial to develop novel multiferroic heterostructures, combining good ferroelectric and ferromagnetic properties as well as a strong coupling between them. For this purpose, Ba₂EuFeNb₄O₁₅/BaFe₁₂O₁₉ multiferroic magnetoelectric bilayers have been epitaxially grown on niobium doped SrTiO₃ (100) single crystal substrates by pulsed laser deposition. The simultaneous presence of both ferroelectric and magnetic properties—due, respectively, to the Ba₂EuFeNb₄O₁₅ and BaFe₁₂O₁₉ components—was demonstrated at room temperature, attesting the multiferroic nature of the heterostructure. More interestingly, a strong magnetoelectric coupling was demonstrated (i) by manipulating the ferroelectric properties via an external magnetic field, and conversely, (ii) by tuning the magnetic properties via an external electric field. This strong magnetoelectric coupling shows the high interdependence of both ferroic orders in the Ba₂EuFeNb₄O₁₅/BaFe₁₂O₁₉ heterostructure, mediated by elastic (epitaxial) strain at the interfaces. Full article

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31 pages, 3962 KiB

Open AccessReview

Tyrosinase Immobilization Strategies for the Development of Electrochemical Biosensors—A Review

by Alexandra Virginia Bounegru and Constantin Apetrei

Nanomaterials 2023, 13(4), 760; https://doi.org/10.3390/nano13040760 - 17 Feb 2023

Cited by 14 | Viewed by 3232

Abstract

The development of enzyme biosensors has successfully overcome various challenges such as enzyme instability, loss of enzyme activity or long response time. In the electroanalytical field, tyrosinase is used to develop biosensors that exploit its ability to catalyze the oxidation of numerous types [...] Read more.

The development of enzyme biosensors has successfully overcome various challenges such as enzyme instability, loss of enzyme activity or long response time. In the electroanalytical field, tyrosinase is used to develop biosensors that exploit its ability to catalyze the oxidation of numerous types of phenolic compounds with antioxidant and neurotransmitter roles. This review critically examines the main tyrosinase immobilization techniques for the development of sensitive electrochemical biosensors. Immobilization strategies are mainly classified according to the degree of reversibility/irreversibility of enzyme binding to the support material. Each tyrosinase immobilization method has advantages and limitations, and its selection depends mainly on the type of support electrode, electrode-modifying nanomaterials, cross-linking agent or surfactants used. Tyrosinase immobilization by cross-linking is characterized by very frequent use with outstanding performance of the developed biosensors. Additionally, research in recent years has focused on new immobilization strategies involving cross-linking, such as cross-linked enzyme aggregates (CLEAs) and magnetic cross-linked enzyme aggregates (mCLEAs). Therefore, it can be considered that cross-linking immobilization is the most feasible and economical approach, also providing the possibility of selecting the reagents used and the order of the immobilization steps, which favor the enhancement of biosensor performance characteristics. Full article

(This article belongs to the Special Issue Nanoparticles for Biosensor Application)

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10 pages, 968 KiB

Open AccessArticle

Integrated Optical Filters with Hyperbolic Metamaterials

by Mas-ud A. Abdulkareem, Fernando López-Rayón, Citlalli T. Sosa-Sánchez, Ramsés E. Bautista González, Maximino L. Arroyo Carrasco, Marycarmen Peña-Gomar, Victor Coello and Ricardo Téllez-Limón

Nanomaterials 2023, 13(4), 759; https://doi.org/10.3390/nano13040759 - 17 Feb 2023

Cited by 4 | Viewed by 2621

Abstract

The growing development of nanotechnology requires the design of new devices that integrate different functionalities at a reduced scale. For on-chip applications such as optical communications or biosensing, it is necessary to selectively transmit a portion of the electromagnetic spectrum. This function is [...] Read more.

The growing development of nanotechnology requires the design of new devices that integrate different functionalities at a reduced scale. For on-chip applications such as optical communications or biosensing, it is necessary to selectively transmit a portion of the electromagnetic spectrum. This function is performed by the so-called band-pass filters. While several plasmonic nanostructures of complex fabrication integrated to optical waveguides have been proposed, hyperbolic metamaterials remain almost unexplored for the design of integrated band-pass filters at optical wavelengths. By making use of the effective medium theory and finite integration technique, in this contribution we numerically study an integrated device consisting of a one-dimensional hyperbolic metamaterial placed on top of a photonic waveguide. The results show that the filling fraction, period, and number of layers modify the spectral response of the device, but not for type II and effective metal metamaterials. For the proposed Au-TiO₂ multilayered system, the filter operates at a wavelength of 760 nm, spectral bandwidth of 100 nm and transmission efficiency above 40%. The designed devices open new perspectives for the development of integrated band-pass filters of small scale for on-chip integrated optics applications. Full article

(This article belongs to the Special Issue Nanophotonics and Integrated Optics Devices)

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13 pages, 7504 KiB

Open AccessArticle

Construction of Hollow Co₃O₄@ZnIn₂S₄ p-n Heterojunctions for Highly Efficient Photocatalytic Hydrogen Production

by Zijian Xin, Haizhao Zheng and Juncheng Hu

Nanomaterials 2023, 13(4), 758; https://doi.org/10.3390/nano13040758 - 17 Feb 2023

Cited by 4 | Viewed by 2320

Abstract

Photocatalysts derived from semiconductor heterojunctions for water splitting have bright prospects in solar energy conversion. Here, a Co₃O₄@ZIS p-n heterojunction was successfully created by developing two-dimensional ZnIn₂S₄ on ZIF-67-derived hollow Co₃O₄ nanocages, realizing [...] Read more.

Photocatalysts derived from semiconductor heterojunctions for water splitting have bright prospects in solar energy conversion. Here, a Co₃O₄@ZIS p-n heterojunction was successfully created by developing two-dimensional ZnIn₂S₄ on ZIF-67-derived hollow Co₃O₄ nanocages, realizing efficient spatial separation of the electron-hole pair. Moreover, the black hollow structure of Co₃O₄ considerably increases the range of light absorption and the light utilization efficiency of the heterojunction avoids the agglomeration of ZnIn₂S₄ nanosheets and further improves the hydrogen generation rate of the material. The obtained Co₃O₄(20) @ZIS showed excellent photocatalytic H₂ activity of 5.38 mmol g⁻¹·h⁻¹ under simulated solar light, which was seven times more than that of pure ZnIn₂S₄. Therefore, these kinds of constructions of hollow p-n heterojunctions have a positive prospect in solar energy conversion fields. Full article

(This article belongs to the Topic Nanomaterials and Catalysts for Clean Fuels and Sustainable Energy)

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14 pages, 3730 KiB

Open AccessEditor’s ChoiceArticle

Selected Area Deposition of High Purity Gold for Functional 3D Architectures

by John Lasseter, Philip D. Rack and Steven J. Randolph

Nanomaterials 2023, 13(4), 757; https://doi.org/10.3390/nano13040757 - 17 Feb 2023

Cited by 4 | Viewed by 2499

Abstract

Selected area deposition of high purity gold films onto nanoscale 3D architectures is highly desirable as gold is conductive, inert, plasmonically active, and can be functionalized with thiol chemistries, which are useful in many biological applications. Here, we show that high-purity gold coatings [...] Read more.

Selected area deposition of high purity gold films onto nanoscale 3D architectures is highly desirable as gold is conductive, inert, plasmonically active, and can be functionalized with thiol chemistries, which are useful in many biological applications. Here, we show that high-purity gold coatings can be selectively grown with the Me₂Au (acac) precursor onto nanoscale 3D architectures via a pulsed laser pyrolytic chemical vapor deposition process. The selected area of deposition is achieved due to the high thermal resistance of the nanoscale geometries. Focused electron beam induced deposits (FEBID) and carbon nanofibers are functionalized with gold coatings, and we demonstrate the effects that laser irradiance, pulse width, and precursor pressure have on the growth rate. Furthermore, we demonstrate selected area deposition with a feature-targeting resolutions of ~100 and 5 µm, using diode lasers coupled to a multimode (915 nm) and single mode (785 nm) fiber optic, respectively. The experimental results are rationalized via finite element thermal modeling. Full article

(This article belongs to the Special Issue Nanomaterials Fabricated by Electron-Beam-Induced Deposition and Related Processes)

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15 pages, 4939 KiB

Open AccessFeature PaperArticle

Particle Debris Generated from Passenger Tires Induces Morphological and Gene Expression Alterations in the Macrophages Cell Line RAW 264.7

by Anna Poma, Massimo Aloisi, Antonella Bonfigli, Sabrina Colafarina, Osvaldo Zarivi, Pierpaolo Aimola, Giulia Vecchiotti, Lorenzo Arrizza, Alessandra Di Cola and Patrizia Cesare

Nanomaterials 2023, 13(4), 756; https://doi.org/10.3390/nano13040756 - 17 Feb 2023

Cited by 6 | Viewed by 2347

Abstract

Air pollution in the urban environment is a topical subject. Aero-suspended particles can cause respiratory diseases in humans, ranging from inflammation to asthma and cancer. One of the components that is most prevalent in particulate matter (PM) in urban areas is the set [...] Read more.

Air pollution in the urban environment is a topical subject. Aero-suspended particles can cause respiratory diseases in humans, ranging from inflammation to asthma and cancer. One of the components that is most prevalent in particulate matter (PM) in urban areas is the set of tire microparticles (1–20 μm) and nanoparticles (<1 μm) that are formed due to the friction of wheels with asphalt and are increased in slow-moving areas that involve a lot of braking actions. In this work, we studied the effect that microparticles generated from passenger tires (PTWP, passenger tire wear particles) have in vitro on murine macrophages cells RAW 264.7 at two concentrations of 25 and 100 μg/mL, for 24 and 48 h. In addition to the chemical characterization of the material and morphological characterization of the treated cells by transmission electron microscopy, gene expression analysis with RT-PCR and active protein analysis with Western blotting were performed. Growth curves were obtained, and the genotoxic effect was evaluated with a comet assay. The results indicate that initially, an induction of the apoptotic process is observable, but this is subsequently reversed by Bcl2. No genotoxic damage is present, but mild cellular abnormalities were observed in the treated cells. Full article

(This article belongs to the Section Biology and Medicines)

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