Nanomaterials

27 pages, 8737 KiB

Open AccessArticle

Ni-Based Molecular Sieves Nanomaterials for Dry Methane Reforming: Role of Porous Structure and Active Sites Distribution on Hydrogen Production

by Ahmed S. Al-Fatesh, Ahmed A. Ibrahim, Anis H. Fakeeha, Ahmed I. Osman, Yousef M. Alanazi, Fahad Saleh Almubaddel and Ahmed E. Abasaeed

Nanomaterials 2024, 14(15), 1320; https://doi.org/10.3390/nano14151320 - 5 Aug 2024

Viewed by 1379

Abstract

Global warming, driven by greenhouse gases like CH₄ and CO₂, necessitates efficient catalytic conversion to syngas. Herein, Ni containing different molecular sieve nanomaterials are investigated for dry reforming of methane (DRM). The reduced catalysts are characterized by surface area porosity, [...] Read more.

Global warming, driven by greenhouse gases like CH₄ and CO₂, necessitates efficient catalytic conversion to syngas. Herein, Ni containing different molecular sieve nanomaterials are investigated for dry reforming of methane (DRM). The reduced catalysts are characterized by surface area porosity, X-ray diffraction, Raman infrared spectroscopy, CO₂ temperature-programmed desorption techniques, and transmission electron microscopy. The active sites over each molecular sieve remain stable under oxidizing gas CO₂ during DRM. The reduced 5Ni/CBV10A catalyst, characterized by the lowest silica–alumina ratio, smallest surface area and pore volume, and narrow 8-ring connecting channels, generated the maximum number of active sites on its outer surface. In contrast, the reduced-5Ni/CBV3024E catalyst, with the highest silica–alumina ratio, more than double the surface area and pore volume, 12-ring sinusoidal porous channels, and smallest Ni crystallite, produced the highest H₂ output (44%) after 300 min of operation at 700 °C, with a CH₄:CO₂ = 1:1, P = 1 atom, gas hour space velocity (GHSV) = 42 L gcat⁻¹ h⁻¹. This performance was achieved despite having 25% fewer initial active sites, suggesting that a larger fraction of these sites is stabilized within the pore channels, leading to sustained catalytic activity. Using central composite design and response surface methodology, we successfully optimized the process conditions for the 5Ni/CBV3024E catalyst. The optimized conditions yielded a desirable H₂ to CO ratio of 1.00, with a H₂ yield of 91.92% and a CO yield of 89.16%, indicating high efficiency in gas production. The experimental results closely aligned with the predicted values, demonstrating the effectiveness of the optimization approach. Full article

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15 pages, 895 KiB

Open AccessArticle

Superconductivity of Co-Doped CaKFe₄As₄ Investigated via Point-Contact Spectroscopy and London Penetration Depth Measurements

by Erik Piatti, Daniele Torsello, Francesca Breccia, Tsuyoshi Tamegai, Gianluca Ghigo and Dario Daghero

Nanomaterials 2024, 14(15), 1319; https://doi.org/10.3390/nano14151319 - 5 Aug 2024

Viewed by 1143

Abstract

The iron-based superconductors (IBSs) of the recently discovered 1144 class, unlike many other IBSs, display superconductivity in their stoichiometric form and are intrinsically hole doped. The effects of chemical substitutions with electron donors are thus particularly interesting to investigate. Here, we study the [...] Read more.

The iron-based superconductors (IBSs) of the recently discovered 1144 class, unlike many other IBSs, display superconductivity in their stoichiometric form and are intrinsically hole doped. The effects of chemical substitutions with electron donors are thus particularly interesting to investigate. Here, we study the effect of Co substitution in the Fe site of

{CaKFe}_{4}

{As}_{4}

single crystals on the critical temperature, on the energy gaps, and on the superfluid density by using transport, point-contact Andreev-reflection spectroscopy (PCARS), and London penetration depth measurements. The pristine compound (

T_{c} ≃ 36

K) shows two isotropic gaps whose amplitudes (

Δ_{1}

= 1.4–3.9 meV and

Δ_{2}

= 5.2–8.5 meV) are perfectly compatible with those reported in the literature. Upon Co doping (up to ≈7% Co),

T_{c}

decreases down to ≃20 K, the spin-vortex-crystal order appears, and the low-temperature superfluid density is gradually suppressed. PCARS and London penetration depth measurements perfectly agree in demonstrating that the nodeless multigap structure is robust upon Co doping, while the gap amplitudes decrease as a function of

T_{c}

in a linear way with almost constant values of the gap ratios

2 Δ_{i} / k_{B} T_{c}

. Full article

(This article belongs to the Special Issue Superconductivity and Magnetism in Two-Dimensional and Layered Materials)

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14 pages, 3306 KiB

Open AccessReview

Fluorescent Nanodiamonds for High-Resolution Thermometry in Biology

by Anna Ermakova

Nanomaterials 2024, 14(15), 1318; https://doi.org/10.3390/nano14151318 - 5 Aug 2024

Viewed by 1343

Abstract

Optically active color centers in diamond and nanodiamonds can be utilized as quantum sensors for measuring various physical parameters, particularly magnetic and electric fields, as well as temperature. Due to their small size and possible surface functionalization, fluorescent nanodiamonds are extremely attractive systems [...] Read more.

Optically active color centers in diamond and nanodiamonds can be utilized as quantum sensors for measuring various physical parameters, particularly magnetic and electric fields, as well as temperature. Due to their small size and possible surface functionalization, fluorescent nanodiamonds are extremely attractive systems for biological and medical applications since they can be used for intracellular experiments. This review focuses on fluorescent nanodiamonds for thermometry with high sensitivity and a nanoscale spatial resolution for the investigation of living systems. The current state of the art, possible further development, and potential limitations of fluorescent nanodiamonds as thermometers will be discussed here. Full article

(This article belongs to the Section 2D and Carbon Nanomaterials)

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12 pages, 4849 KiB

Open AccessArticle

Design of Ultra-Compact and Multifunctional Optical Logic Gate Based on Sb₂Se₃-SOI Hybrid Platform

by Liuni Yang, Qiang Liu, Haoyuan Liang, Minming Geng, Kejin Wei and Zhenrong Zhang

Nanomaterials 2024, 14(15), 1317; https://doi.org/10.3390/nano14151317 - 5 Aug 2024

Viewed by 1087

Abstract

Optical logic devices are essential functional devices for achieving optical signal processing. In this study, we design an ultra-compact (4.92 × 2.52 μm²) reconfigurable optical logic gate by using inverse design method with DBS algorithm based on Sb₂Se₃ [...] Read more.

Optical logic devices are essential functional devices for achieving optical signal processing. In this study, we design an ultra-compact (4.92 × 2.52 μm²) reconfigurable optical logic gate by using inverse design method with DBS algorithm based on Sb₂Se₃-SOI integrated platform. By selecting different amorphous/crystalline distributions of Sb₂Se₃ via programmable electrical triggers, the designed structure can switch between OR, XOR, NOT or AND logic gate. This structure works well for all four logic functions in the wavelength range of 1540–1560 nm. Especially at the wavelength of 1550 nm, the Contrast Ratios for XOR, NOT and AND logic gate are 13.77 dB, 11.69 dB and 3.01 dB, respectively, indicating good logical judgment ability of the device. Our design is robust to a certain range of fabrication imperfections. Even if performance weakens due to deviations, improvements can be obtained by rearranging the configurations of Sb₂Se₃ without reproducing the whole device. Full article

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12 pages, 3384 KiB

Open AccessArticle

A Mid-Infrared Perfect Metasurface Absorber with Tri-Band Broadband Scalability

by Yongtu Zou, Shaolin Zhou, Jingxi Li, Shanri Chen and Zhijian Chen

Nanomaterials 2024, 14(15), 1316; https://doi.org/10.3390/nano14151316 - 5 Aug 2024

Cited by 1 | Viewed by 1417

Abstract

Metasurfaces have emerged as a unique group of two-dimensional ultra-compact subwavelength devices for perfect wave absorption due to their exceptional capabilities of light modulation. Nonetheless, achieving high absorption, particularly with multi-band broadband scalability for specialized scenarios, remains a challenge. As an example, the [...] Read more.

Metasurfaces have emerged as a unique group of two-dimensional ultra-compact subwavelength devices for perfect wave absorption due to their exceptional capabilities of light modulation. Nonetheless, achieving high absorption, particularly with multi-band broadband scalability for specialized scenarios, remains a challenge. As an example, the presence of atmospheric windows, as dictated by special gas molecules in different infrared regions, highly demands such scalable modulation abilities for multi-band absorption and filtration. Herein, by leveraging the hybrid effect of Fabry–Perot resonance, magnetic dipole resonance and electric dipole resonance, we achieved multi-broadband absorptivity in three prominent infrared atmospheric windows concurrently, with an average absorptivity of 87.6% in the short-wave infrared region (1.4–1.7 μm), 92.7% in the mid-wave infrared region (3.2–5 μm) and 92.4% in the long-wave infrared region (8–13 μm), respectively. The well-confirmed absorption spectra along with its adaptation to varied incident angles and polarization angles of radiations reveal great potential for fields like infrared imaging, photodetection and communication. Full article

(This article belongs to the Special Issue Nonlinear Optics of Nanostructures and Metasurfaces)

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12 pages, 4481 KiB

Open AccessArticle

Large-Area Perovskite Solar Module Produced by Introducing Self-Assembled L-Histidine Monolayer at TiO₂ and Perovskite Interface

by Hung-Chieh Hsu, Jung-Che Tsao, Cheng-Hsien Yeh, Hsuan-Ta Wu, Chien-Te Wu, Shih-Hsiung Wu and Chuan-Feng Shih

Nanomaterials 2024, 14(15), 1315; https://doi.org/10.3390/nano14151315 - 4 Aug 2024

Viewed by 1892

Abstract

Perovskite solar cells have been proven to enhance cell characteristics by introducing passivation materials that suppress defect formation. Defect states between the electron transport layer and the absorption layer reduce electron extraction and carrier transport capabilities, leading to a significant decline in device [...] Read more.

Perovskite solar cells have been proven to enhance cell characteristics by introducing passivation materials that suppress defect formation. Defect states between the electron transport layer and the absorption layer reduce electron extraction and carrier transport capabilities, leading to a significant decline in device performance and stability, as well as an increased probability of non-radiative recombination. This study proposes the use of an amino acid (L-Histidine) self-assembled monolayer material between the transport layer and the perovskite absorption layer. Surface analysis revealed that the introduction of L-Histidine improved both the uniformity and roughness of the perovskite film surface. X-ray photoelectron spectroscopic analysis showed a reduction in oxygen vacancies in the lattice and an increase in Ti⁴⁺, indicating that L-Histidine successfully passivated trap states at the perovskite and TiO₂ electron transport layer interface. In terms of device performance, the introduction of L-Histidine significantly improved the fill factor (FF) because the reduction in interface defects could suppress charge accumulation and reduce device hysteresis. The FF of large-area solar modules (25 cm²) with L-Histidine increased from 55% to 73%, and the power conversion efficiency (PCE) reached 16.5%. After 500 h of aging tests, the PCE still maintained 91% of its original efficiency. This study demonstrates the significant impact of L-Histidine on transport properties and showcases its potential for application in the development of large-area perovskite module processes. Full article

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9 pages, 1712 KiB

Open AccessArticle

An Organic Microcavity Laser Amplifier Integrated on the End Facet of an Optical Fiber

by Meng Wang, Zhuangzhuang Xu, Yaqi Ren, Xiaolei Bai and Xinping Zhang

Nanomaterials 2024, 14(15), 1314; https://doi.org/10.3390/nano14151314 - 4 Aug 2024

Viewed by 1207

Abstract

We report a thin-film optical amplifier integrated on a fiber facet based on polymer-coated distributed feedback (DFB) microcavities, which are fabricated on a planar substrate and then transferred onto fiber tips by means of a flexible transfer technique. The amplified light directly couples [...] Read more.

We report a thin-film optical amplifier integrated on a fiber facet based on polymer-coated distributed feedback (DFB) microcavities, which are fabricated on a planar substrate and then transferred onto fiber tips by means of a flexible transfer technique. The amplified light directly couples into the fiber and is detected when coupled out at the other end after propagating along the fiber for about 20 cm. A prominently amplification factor of about 4.33 at 578.57 nm is achieved by sending supercontinuum pulses into the hundreds of micrometers’ DFB microcavities along the normal direction, which is also the axis direction of the fiber. The random distortions of grating lines generated during the transfer process result in a larger amplification spectral range and a less strict polarization dependence for injected light. Benefitting from the device size of hundreds of micrometers and the ease of integration, polymer amplifiers based on DFB microcavities demonstrate significant application potentials in optical communication systems and miniaturized optical devices. Full article

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15 pages, 3526 KiB

Open AccessArticle

Plasma Modification of Biomass-Based Starfish Catalysts for Efficient Biodiesel Synthesis

by Sungho Lee, Jeyoung Ha and Oi Lun Li

Nanomaterials 2024, 14(15), 1313; https://doi.org/10.3390/nano14151313 - 4 Aug 2024

Viewed by 1117

Abstract

This study investigated biodiesel production via the transesterification of grapeseed oil with plasma-modified biomass-based catalysts originating from starfish. Dried starfish was first converted into magnesium and calcium oxide through heat treatment and then further modified by plasma engineering to improve the catalyst’s surface [...] Read more.

This study investigated biodiesel production via the transesterification of grapeseed oil with plasma-modified biomass-based catalysts originating from starfish. Dried starfish was first converted into magnesium and calcium oxide through heat treatment and then further modified by plasma engineering to improve the catalyst’s surface area and active sites via zinc addition. The Zn content was added via plasma engineering in the ratios of starfish (Mg_0.1Ca_0.9CO₃): ZnO varying from 5:1, 10:1, to 20:1. The structure and morphology of the catalyst were confirmed through XRD, SEM, and XPS analysis. After the Zn addition and activation process, the surface area and the basicity of the synthesized catalysts were increased. The plasma-modified catalyst showed the highest basicity at the ratio of 10:1. Based on HPLC analyses, the optimized biodiesel yield in transesterification demonstrated 97.7% in fatty acid conversion, and its catalytic performance maintained 93.2% even after three repeated runs. Full article

(This article belongs to the Topic Biomass for Energy, Chemicals and Materials)

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11 pages, 3214 KiB

Open AccessArticle

Highly Efficient Peroxymonosulfate Electroactivation on Co(OH)₂ Nanoarray Electrode for Pefloxacin Degradation

by Tonghui Bao, Hui Ke, Wanjiang Li, Linke Cai and Yi Huang

Nanomaterials 2024, 14(15), 1312; https://doi.org/10.3390/nano14151312 - 4 Aug 2024

Viewed by 1042

Abstract

The activation of PMS to produce active species is an attractive technique for antibiotic degradation but is restricted to the low reaction kinetics and high costs. In this work, a cobalt-based catalyst was prepared by in situ electrodeposition to enhance the electrically activated [...] Read more.

The activation of PMS to produce active species is an attractive technique for antibiotic degradation but is restricted to the low reaction kinetics and high costs. In this work, a cobalt-based catalyst was prepared by in situ electrodeposition to enhance the electrically activated PMS process for the degradation of antibiotics. Almost 100% of pefloxacin (PFX) was removed within 10 min by employing Co(OH)₂ as the catalyst in the electrically activated peroxymonosulfate (PMS) process, and the reaction kinetic constant reached 0.52 min⁻¹. The redox processes of Co²⁺ and Co³⁺ in Co(OH)₂ catalysts were considered to be the main pathways for PMS activation, in which ¹O₂ was the main active species. Furthermore, this strategy could also achieve excellent degradation efficiency for other organic pollutants. This study provides an effective and low-cost strategy with no secondary pollution for pollutant degradation. Full article

(This article belongs to the Special Issue Functional Nanostructured Electro/Photocatalysts for Energy Conversion and Environmental Treatment)

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13 pages, 1507 KiB

Open AccessReview

Iron Oxide Nanoparticles as Promising Antibacterial Agents of New Generation

by Tian-Guang Zhang and Chao-Yu Miao

Nanomaterials 2024, 14(15), 1311; https://doi.org/10.3390/nano14151311 - 3 Aug 2024

Cited by 2 | Viewed by 1836

Abstract

Antimicrobial resistance (AMR) is growing into a major public health crisis worldwide. The reducing alternatives to conventional agents starve for novel antimicrobial agents. Due to their unique magnetic properties and excellent biocompatibility, iron oxide nanoparticles (IONPs) are the most preferable nanomaterials in biomedicine, [...] Read more.

Antimicrobial resistance (AMR) is growing into a major public health crisis worldwide. The reducing alternatives to conventional agents starve for novel antimicrobial agents. Due to their unique magnetic properties and excellent biocompatibility, iron oxide nanoparticles (IONPs) are the most preferable nanomaterials in biomedicine, including antibacterial therapy, primarily through reactive oxygen species (ROS) production. IONP characteristics, including their size, shape, surface charge, and superparamagnetism, influence their biodistribution and antibacterial activity. External magnetic fields, foreign metal doping, and surface, size, and shape modification improve the antibacterial effect of IONPs. Despite a few disadvantages, IONPs are expected to be promising antibacterial agents of a new generation. Full article

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14 pages, 10436 KiB

Open AccessArticle

Impact of Residual Strains on the Carrier Mobility and Stability of Perovskite Films

by Moulay Ahmed Slimani, Luis Felipe Gerlein, Ricardo Izquierdo and Sylvain G. Cloutier

Nanomaterials 2024, 14(15), 1310; https://doi.org/10.3390/nano14151310 - 3 Aug 2024

Viewed by 1127

Abstract

Solution-based inorganic–organic halide perovskites are of great interest to researchers because of their unique optoelectronic properties and easy processing. However, polycrystalline perovskite films often show inhomogeneity due to residual strain induced during the film’s post-processing phase. In turn, these strains can impact both [...] Read more.

Solution-based inorganic–organic halide perovskites are of great interest to researchers because of their unique optoelectronic properties and easy processing. However, polycrystalline perovskite films often show inhomogeneity due to residual strain induced during the film’s post-processing phase. In turn, these strains can impact both their stability and performance. An exhaustive study of residual strains can provide a better understanding and control of how they affect the performance and stability of perovskite films. In this work, we explore this complex interrelationship between residual strains and electrical properties for methylammonium

{CH}_{3} {NH}_{3} {PbI}_{3 - x} {Cl}_{x}

films using grazing incidence X-ray diffraction (GIXRD). We correlate their resistivity and carrier mobility using the Hall effect. The

\sin^{2} (ψ)

technique is used to optimize the annealing parameters for the perovskite films. We also establish that temperature-induced relaxation can yield a significant enhancement of the charge carrier transports in perovskite films. Finally, we also use Raman micro-spectroscopy to assess the degradation of perovskite films as a function of their residual strains. Full article

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15 pages, 4063 KiB

Open AccessArticle

Nanotechnological Antibacterial and Conductive Wound Dressings for Pressure Ulcer Prevention

by Mauro Pollini, Raffaella Striani, Federica Paladini, Aida Kiani, Maria Rosaria Acocella and Carola Esposito Corcione

Nanomaterials 2024, 14(15), 1309; https://doi.org/10.3390/nano14151309 - 3 Aug 2024

Viewed by 1380

Abstract

The development of pressure ulcers, associated with increased temperature and moisture in specific areas of the body, and the risk of microbial infections in patients lying in a static position for prolonged periods of time represents a serious issue in medicine. In order [...] Read more.

The development of pressure ulcers, associated with increased temperature and moisture in specific areas of the body, and the risk of microbial infections in patients lying in a static position for prolonged periods of time represents a serious issue in medicine. In order to prevent the formation of pressure ulcers, this work aims to present advanced nanostructured coatings developed by three research groups. Nanometric silver, ash and functionalized torrefied biomass were the basis for the treatment of wound dressings to improve thermal conductivity and antimicrobial properties of the conventional cotton gauzes. Each treatment was performed according to its own optimized method. The treated fabrics were characterized in terms of antimicrobial properties, heat transfer, morphology and hydrophobic behavior. The results demonstrated the effectiveness of the deposition treatments also in synergistic actions. In particular, the antibacterial efficacy was improved in all the samples by the addition of silver treatment, and the thermal conductivity was enhanced by around 58% with nanometric ashes. A further step of the study involved the designing of two multilayer systems evaluated using circuit models for determining the total thermal conductivity. In this way, both systems were designed with the aim to guarantee simultaneous efficacy: high antibacterial and hydrophilic properties at the skin level and more hydrophobic and conductive behaviors toward the external environment. Full article

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16 pages, 5814 KiB

Open AccessArticle

Nano-Biochar Prepared from High-Pressure Homogenization Improves Thermal Conductivity of Ethylene Glycol-Based Coolant

by Youheng Wang, Xianjun Hou, Hong Yu, Weiwei Guan, Yuxin Ma and Mohamed Kamal Ahmed Ali

Nanomaterials 2024, 14(15), 1308; https://doi.org/10.3390/nano14151308 - 3 Aug 2024

Viewed by 1022

Abstract

As an environmentally friendly material, biochar is increasingly being utilized in the field of heat transfer and thermal conduction. In this study, nano-biochar was prepared from high-pressure homogenization (HPH) using sesame stalks as the raw material. It was incorporated into ethylene glycol (EG) [...] Read more.

As an environmentally friendly material, biochar is increasingly being utilized in the field of heat transfer and thermal conduction. In this study, nano-biochar was prepared from high-pressure homogenization (HPH) using sesame stalks as the raw material. It was incorporated into ethylene glycol (EG) and its dispersion stability, viscosity, and thermal conductivity were investigated. The nano-biochar was stably dispersed in EG for 28 days. When the concentration of the nano-biochar added to EG was less than 1%, the impact on viscosity was negligible. The addition of 5 wt.% nano-biochar to EG improved the thermal conductivity by 6.72%, which could be attributed to the graphitized structure and Brownian motion of the nano-biochar. Overall, nano-biochar has the potential to be applied in automotive thermal management. Full article

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12 pages, 5753 KiB

Open AccessArticle

A Study on Dual-Gate Dielectric Face Tunnel Field-Effect Transistor for Ternary Inverter

by Aoxuan Wang, Hongliang Lu, Yuming Zhang, Jiale Sun and Zhijun Lv

Nanomaterials 2024, 14(15), 1307; https://doi.org/10.3390/nano14151307 - 3 Aug 2024

Viewed by 929

Abstract

In this article, we propose a dual-gate dielectric face tunnel field-effect transistor (DGDFTFET) that can exhibit three different output voltage states. Meanwhile, according to the requirements of the ternary operation in the ternary inverter, four related indicators representing the performance of the DGDFTFET [...] Read more.

In this article, we propose a dual-gate dielectric face tunnel field-effect transistor (DGDFTFET) that can exhibit three different output voltage states. Meanwhile, according to the requirements of the ternary operation in the ternary inverter, four related indicators representing the performance of the DGDFTFET are proposed, and we explain the impact of these indicators on the inverter and confirm that better indicators can be obtained by choosing appropriate design parameters for the device. Then, the ternary inverter implemented with this device can exhibit voltage transfer characteristics (VTCs) with three stable output voltage levels and bigger static noise margins (SNMs). In addition, by comparing the indicators of the DGDFTFET and a face tunnel field-effect transistor (FTFET), as well as the SNM of inverters, it is demonstrated that the performance of the DGDFTFET far surpasses the FTFET. Full article

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11 pages, 3469 KiB

Open AccessArticle

Tunable Ag Nanocavity Enhanced Green Electroluminescence from SiN_x:O Light-Emitting Diode

by Zongyan Zuo, Zhongyuan Ma, Tong Chen, Wenping Zhang, Wei Li, Jun Xu, Ling Xu and Kunji Chen

Nanomaterials 2024, 14(15), 1306; https://doi.org/10.3390/nano14151306 - 3 Aug 2024

Viewed by 1149

Abstract

As the driving source, highly efficient silicon-based light emission is urgently needed for the realization of optoelectronic integrated chips. Here, we report that enhanced green electroluminescence (EL) can be obtained from oxygen-doped silicon nitride (SiN_x:O) films based on an ordered and [...] Read more.

As the driving source, highly efficient silicon-based light emission is urgently needed for the realization of optoelectronic integrated chips. Here, we report that enhanced green electroluminescence (EL) can be obtained from oxygen-doped silicon nitride (SiN_x:O) films based on an ordered and tunable Ag nanocavity array with a high density by nanosphere lithography and laser irradiation. Compared with that of a pure SiN_xO device, the green electroluminescence (EL) from the SiN_x:O/Ag nanocavity array device can be increased by 7.1-fold. Moreover, the external quantum efficiency of the green electroluminescence (EL) is enhanced 3-fold for SiN_x:O/Ag nanocavity arrays with diameters of 300 nm. The analysis of absorption spectra and the FDTD calculation reveal that the localized surface plasmon (LSP) resonance of size-controllable Ag nanocavity arrays and SiN_x:O films play a key role in the strong green EL. Our discovery demonstrates that SiN_x:O films coupled with tunable Ag nanocavity arrays are promising for silicon-based light-emitting diode devices of the AI period in the future. Full article

(This article belongs to the Section Nanocomposite Materials)

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22 pages, 3394 KiB

Open AccessReview

Cancer Treatment Using Nanofibers: A Review

by Muhammad Qamar Khan, Muhammad Abbas Alvi, Hafiza Hifza Nawaz and Muhammad Umar

Nanomaterials 2024, 14(15), 1305; https://doi.org/10.3390/nano14151305 - 2 Aug 2024

Viewed by 1247

Abstract

Currently, the number of patients with cancer is expanding consistently because of a low quality of life. For this reason, the therapies used to treat cancer have received a lot of consideration from specialists. Numerous anticancer medications have been utilized to treat patients [...] Read more.

Currently, the number of patients with cancer is expanding consistently because of a low quality of life. For this reason, the therapies used to treat cancer have received a lot of consideration from specialists. Numerous anticancer medications have been utilized to treat patients with cancer. However, the immediate utilization of anticancer medicines leads to unpleasant side effects for patients and there are many restrictions to applying these treatments. A number of polymers like cellulose, chitosan, Polyvinyl Alcohol (PVA), Polyacrylonitrile (PAN), peptides and Poly (hydroxy alkanoate) have good properties for the treatment of cancer, but the nanofibers-based target and controlled drug delivery system produced by the co-axial electrospinning technique have extraordinary properties like favorable mechanical characteristics, an excellent release profile, a high surface area, and a high sponginess and are harmless, bio-renewable, biofriendly, highly degradable, and can be produced very conveniently on an industrial scale. Thus, nanofibers produced through coaxial electrospinning can be designed to target specific cancer cells or tissues. By modifying the composition and properties of the nanofibers, researchers can control the release kinetics of the therapeutic agent and enhance its accumulation at the tumor site while minimizing systemic toxicity. The core–shell structure of coaxial electrospun nanofibers allows for a controlled and sustained release of therapeutic agents over time. This controlled release profile can improve the efficacy of cancer treatment by maintaining therapeutic drug concentrations within the tumor microenvironment for an extended period. Full article

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16 pages, 6275 KiB

Open AccessArticle

Effect of Titanium Dioxide Particles on the Thermal Stability of Silica Aerogels

by Caide Fan, Jialu Lu, Chengjie Duan, Chengbin Wu, Jiming Lin, Ruoxiang Qiu, Zehui Zhang, Jianming Yang, Bin Zhou and Ai Du

Nanomaterials 2024, 14(15), 1304; https://doi.org/10.3390/nano14151304 - 2 Aug 2024

Viewed by 1258

Abstract

Silica aerogels exhibit a unique nanostructure with low thermal conductivity and low density, making them attractive materials for thermal isolation under extreme conditions. The TiO₂ particle is one of the common industrial additives used to reduce the thermal radiation of aerogel composites [...] Read more.

Silica aerogels exhibit a unique nanostructure with low thermal conductivity and low density, making them attractive materials for thermal isolation under extreme conditions. The TiO₂ particle is one of the common industrial additives used to reduce the thermal radiation of aerogel composites under high-temperature environments, but its influence on thermal resistance is almost unknown. Herein, we report the effect of TiO₂ nanoparticles with different crystal phases and different sizes on the thermal stability of silica aerogel composites. By adding TiO₂ nanoparticles, the aerogel can significantly resist collapse at high temperatures (up to 1000 °C). And compared with the rutile phase TiO₂, the anatase phase TiO₂ shows much higher temperature resistance performance, with shrinkage of only one-sixth of the rutile phase after 800 °C treatment. Interestingly, energy-dispersive spectrometer mapping results show that after 800 °C treatment, silica nanoparticles (NPs) are squeezed out in between anatase TiO₂ particles, which resists the coarsening of silica NPs and ultimately enhances the stability of aerogel composites. The optimal anatase phase TiO₂-doped silica aerogel demonstrates the integrated properties of crack-free morphology (2.84% shrinkage), low thermal conductivity (29.30 mW/(m·K)) and low density (149.4 mg/cm³) after 800 °C treatment. This study may provide new insights for developing oxide-doped silica aerogels with both high-temperature resistance and low thermal radiation. Full article

(This article belongs to the Special Issue Nanomaterials in Aerogel Composites)

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39 pages, 15549 KiB

Open AccessReview

An Outlook on Platinum-Based Active Ingredients for Dermatologic and Skincare Applications

by Shining Li, Yizhou Liu, Ying Wu, Lu Ren, Yongjie Lu, Shuji Yamaguchi, Qipeng Lu, Chuangang Hu, Dongcui Li and Naisheng Jiang

Nanomaterials 2024, 14(15), 1303; https://doi.org/10.3390/nano14151303 - 2 Aug 2024

Viewed by 2758

Abstract

Platinum-based materials exhibit a broad spectrum of biological activities, including antioxidant, anti-inflammatory, antimicrobial, and pro-collagen synthesis properties, making them particularly useful for various biomedical applications. This review summarizes the biological effects and therapeutic potential of platinum-based active ingredients in dermatological and skincare applications. [...] Read more.

Platinum-based materials exhibit a broad spectrum of biological activities, including antioxidant, anti-inflammatory, antimicrobial, and pro-collagen synthesis properties, making them particularly useful for various biomedical applications. This review summarizes the biological effects and therapeutic potential of platinum-based active ingredients in dermatological and skincare applications. We discuss their synthesis methods and their antioxidant, anti-inflammatory, antimicrobial, and collagen synthesis properties, which play essential roles in treating skin conditions including psoriasis and acne, as well as enhancing skin aesthetics in anti-aging products. Safety and sustainability concerns, including the need for green synthesis and comprehensive toxicological assessments to ensure safe topical applications, are also discussed. By providing an up-to-date overview of current research, we aim to highlight both the potential and the current challenges of platinum-based active ingredients in advancing dermatology and skincare solutions. Full article

(This article belongs to the Special Issue Functional Nanoparticles for Biomedical and Nanomedicine Application)

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16 pages, 4077 KiB

Open AccessArticle

Reverse Electrodialysis with Continuous Random Variation in Nanochannel Shape: Salinity Gradient-Driven Power Generation

by Runchen Zhao, Jinhui Zhou, Tianqi Bu, Hao Li and Yanmei Jiao

Nanomaterials 2024, 14(15), 1302; https://doi.org/10.3390/nano14151302 - 2 Aug 2024

Viewed by 1111

Abstract

The shape of nanochannels plays a crucial role in the ion selectivity and overall performance of reverse electrodialysis (RED) systems. However, current research on two-dimensional nanochannel shapes is largely limited to a few fixed asymmetric forms. This study explores the impact of randomly [...] Read more.

The shape of nanochannels plays a crucial role in the ion selectivity and overall performance of reverse electrodialysis (RED) systems. However, current research on two-dimensional nanochannel shapes is largely limited to a few fixed asymmetric forms. This study explores the impact of randomly shaped nanochannels using dimensionless methods, controlling their randomness by varying their length and shape amplitude. The research systematically compares how alterations in the nanochannel length and shape amplitude influence various system performance parameters. Our findings indicate that increasing the nanochannel length can significantly enhance the system performance. While drastic changes in the nanochannel shape amplitude positively affect the system performance, the most significant improvements arise from the interplay between the nanochannel length and shape amplitude. This compounding effect creates a local optimum, resulting in peak system performance. Within the range of dimensionless lengths from 0 to 30, the system reaches its optimal performance at a dimensionless length of approximately 25. Additionally, we explored two other influencing factors: the nanochannel surface charge density and the concentration gradient of the solution across the nanochannel. Optimal performance is observed when the nanochannel has a high surface charge density and a low concentration gradient, particularly with random shapes. This study advances the theoretical understanding of RED systems in two-dimensional nanochannels, guiding research towards practical operational conditions. Full article

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14 pages, 3189 KiB

Open AccessArticle

Optimizing Geometry and ETL Materials for High-Performance Inverted Perovskite Solar Cells by TCAD Simulation

by Irodakhon Gulomova, Oussama Accouche, Rayimjon Aliev, Zaher Al Barakeh and Valikhon Abduazimov

Nanomaterials 2024, 14(15), 1301; https://doi.org/10.3390/nano14151301 - 2 Aug 2024

Cited by 1 | Viewed by 1400

Abstract

Due to the optical properties of the electron transport layer (ETL) and hole transport layer (HTL), inverted perovskite solar cells can perform better than traditional perovskite solar cells. It is essential to compare both types to understand their efficiencies. In this article, we [...] Read more.

Due to the optical properties of the electron transport layer (ETL) and hole transport layer (HTL), inverted perovskite solar cells can perform better than traditional perovskite solar cells. It is essential to compare both types to understand their efficiencies. In this article, we studied inverted perovskite solar cells with NiO_x/CH₃NH₃Pb₃/ETL (ETL = MoO₃, TiO₂, ZnO) structures. Our results showed that the optimal thickness of NiO_x is 80 nm for all structures. The optimal perovskite thickness is 600 nm for solar cells with ZnO and MoO₃, and 800 nm for those with TiO₂. For the ETLs, the best thicknesses are 100 nm for ZnO, 80 nm for MoO₃, and 60 nm for TiO₂. We found that the efficiencies of inverted perovskite solar cells with ZnO, MoO₃, and TiO₂ as ETLs, and with optimal layer thicknesses, are 30.16%, 18.69%, and 35.21%, respectively. These efficiencies are 1.5%, 5.7%, and 1.5% higher than those of traditional perovskite solar cells. Our study highlights the potential of optimizing layer thicknesses in inverted perovskite solar cells to achieve higher efficiencies than traditional structures. Full article

(This article belongs to the Special Issue Advances in Semiconductor Materials for Perovskite Solar Cells)

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30 pages, 3367 KiB

Open AccessReview

Nanogels: Recent Advances in Synthesis and Biomedical Applications

by Pasquale Mastella, Biagio Todaro and Stefano Luin

Nanomaterials 2024, 14(15), 1300; https://doi.org/10.3390/nano14151300 - 1 Aug 2024

Cited by 1 | Viewed by 2643

Abstract

In the context of advanced nanomaterials research, nanogels (NGs) have recently gained broad attention for their versatility and promising biomedical applications. To date, a significant number of NGs have been developed to meet the growing demands in various fields of biomedical research. Summarizing [...] Read more.

In the context of advanced nanomaterials research, nanogels (NGs) have recently gained broad attention for their versatility and promising biomedical applications. To date, a significant number of NGs have been developed to meet the growing demands in various fields of biomedical research. Summarizing preparation methods, physicochemical and biological properties, and recent applications of NGs may be useful to help explore new directions for their development. This article presents a comprehensive overview of the latest NG synthesis methodologies, highlighting advances in formulation with different types of hydrophilic or amphiphilic polymers. It also underlines recent biomedical applications of NGs in drug delivery and imaging, with a short section dedicated to biosafety considerations of these innovative nanomaterials. In conclusion, this article summarizes recent innovations in NG synthesis and their numerous applications, highlighting their considerable potential in the biomedical field. Full article

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16 pages, 12522 KiB

Open AccessArticle

Hydrothermal Synthesis of β-NiS Nanoparticles and Their Applications in High-Performance Hybrid Supercapacitors

by Xiaohong Liu, Yulin Wang, Chunwang Luo, Zheyu Zhang, Hongyan Sun, Chunju Xu and Huiyu Chen

Nanomaterials 2024, 14(15), 1299; https://doi.org/10.3390/nano14151299 - 1 Aug 2024

Viewed by 1298

Abstract

In this work, β-NiS nanoparticles (NPs) were efficiently prepared by a straightforward hydrothermal process. The difference in morphology between these NiS NPs was produced by adding different amounts of thiourea, and the corresponding products were denoted as NiS-15 and NiS-5. Through electrochemical tests, [...] Read more.

In this work, β-NiS nanoparticles (NPs) were efficiently prepared by a straightforward hydrothermal process. The difference in morphology between these NiS NPs was produced by adding different amounts of thiourea, and the corresponding products were denoted as NiS-15 and NiS-5. Through electrochemical tests, the specific capacity (C_s) of NiS-15 was determined to be 638.34 C g⁻¹ at 1 A g⁻¹, compared to 558.17 C g⁻¹ for NiS-5. To explore the practical application potential of such β-NiS NPs in supercapacitors, a hybrid supercapacitor (HSC) device was assembled with activated carbon (AC) as an anode. Benefitting from the high capacity of the NiS cathode and the large voltage window of the device, the NiS-15//AC HSC showed a high energy density (E_d) of 43.57 W h kg⁻¹ at 936.92 W kg⁻¹, and the NiS-5//AC HSC provided an inferior E_d of 37.89 W h kg⁻¹ at 954.79 W kg⁻¹. Both HSCs showed excellent cycling performance over 6000 cycles at 10 A g⁻¹. The experimental findings suggest that both NiS-15 and NiS-5 in this study can serve as potential cathodes for high-performance supercapacitors. This current synthesis method is simple and can be extended to the preparation of other transition metal sulfide (TMS)-based electrode materials with exceptional electrochemical properties. Full article

(This article belongs to the Special Issue Nanomaterials for Supercapacitors)

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23 pages, 4546 KiB

Open AccessEditor’s ChoiceArticle

Enhanced Dye Adsorption on Cold Plasma-Oxidized Multi-Walled Carbon Nanotubes: A Comparative Study

by Anastasia Skourti, Stefania Giannoulia, Maria K. Daletou and Christos A. Aggelopoulos

Nanomaterials 2024, 14(15), 1298; https://doi.org/10.3390/nano14151298 - 1 Aug 2024

Cited by 1 | Viewed by 1249

Abstract

The oxidation of multi-walled carbon nanotubes (MWCNTs) using cold plasma was investigated for their subsequent use as adsorbents for the removal of dyes from aqueous solutions. The properties of MWCNTs after plasma modification and their adsorption capacities were compared with pristine and chemically [...] Read more.

The oxidation of multi-walled carbon nanotubes (MWCNTs) using cold plasma was investigated for their subsequent use as adsorbents for the removal of dyes from aqueous solutions. The properties of MWCNTs after plasma modification and their adsorption capacities were compared with pristine and chemically oxidized nanotubes. The modification process employed a reactor where plasma was generated through dielectric barrier discharges (DBD) powered by high-voltage nanosecond pulses. Various modification conditions were examined, such as processing time and pulse voltage amplitude. The degree of oxidation and the impact on the chemistry and structure of the nanotubes was investigated through various physicochemical and morphological characterization techniques (XPS, BET, TEM, etc.). Maximum oxidation (O/C = 0.09 from O/C = 0.02 for pristine MWCNTs) was achieved after 60 min of nanopulsed-DBD plasma treatment. Subsequently, the modified nanotubes were used as adsorbents for the removal of the dye methylene blue (MB) from water. The adsorption experiments examined the effects of contact time between the adsorbent and MB, as well as the initial dye concentration in water. The plasma-modified nanotubes exhibited high MB removal efficiency, with adsorption capacity proportional to the degree of oxidation. Notably, their adsorption capacity significantly increased compared to both pristine and chemically oxidized MWCNTs (~54% and ~9%, respectively). Finally, the kinetics and mechanism of the adsorption process were studied, with experimental data fitting well to the pseudo-second-order kinetic model and the Langmuir isotherm model. This study underscores the potential of plasma technology as a low-cost and environmentally friendly approach for material modification and water purification. Full article

(This article belongs to the Special Issue Novel Nanostructured Materials and Their Applications in Wastewater Treatment)

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18 pages, 14118 KiB

Open AccessArticle

The Preparation of a Polyamidoxime–Phosphorylated Cellulose Nanofibrils Composite Aerogel for the Selective Extraction of Uranium from Seawater

by Xiaoying Yang, Mei Cui, Rongxin Su and Renliang Huang

Nanomaterials 2024, 14(15), 1297; https://doi.org/10.3390/nano14151297 - 1 Aug 2024

Viewed by 1303

Abstract

Uranium is the most important fuel for nuclear power operations, and the safe supply of its resources is the key to the development of nuclear power in China. Because of the complex seawater environment and extremely low uranium concentration, extracting uranium from natural [...] Read more.

Uranium is the most important fuel for nuclear power operations, and the safe supply of its resources is the key to the development of nuclear power in China. Because of the complex seawater environment and extremely low uranium concentration, extracting uranium from natural seawater poses a significant challenge. In this study, a polyamidoxime–phosphorylated cellulose nanofibril composite aerogel was prepared as an adsorbent for uranium extraction from seawater. An adsorption kinetics test, equilibrium adsorption isotherm model fitting, an adsorption–desorption cycle test, and a selectivity test were carried out to evaluate the adsorption performance of the composite aerogel for uranium extraction. The adsorption capacities for the initial concentrations of 4 and 8 ppm in uranium-spiked pure water were 96.9 and 204.3 mg-U/g-Ads, respectively. The equilibrium uranium adsorption capacities of uranium-spiked simulated seawater were 38.9 and 51.7 mg-U/g-Ads, respectively. The distribution coefficient K_D of uranium was calculated to be 2.5 × 10⁷ mL/g. The results show that the polyamidoxime–phosphorylated cellulose nanofiber composite aerogels prepared in this study have the advantages of low cost and high uranium selectivity for uranium extraction from seawater. Full article

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18 pages, 11111 KiB

Open AccessArticle

Enhancing Strength and Ductility of a Ni-26.6Co-18.4Cr-4.1Mo-2.3Al-0.3Ti-5.4Nb Alloy via Nanosized Precipitations, Stacking Faults, and Nanotwins

by Jingjing Zhang, Yongfeng Shen, Wenying Xue and Zhijian Fan

Nanomaterials 2024, 14(15), 1296; https://doi.org/10.3390/nano14151296 - 31 Jul 2024

Cited by 1 | Viewed by 1156

Abstract

The addition of Co to Ni-based alloys can reduce the stacking fault energy. In this study, a novel Ni-26.6Co-18.4Cr-4.1Mo-2.3Al-0.3Ti-5.4Nb alloy was developed by increasing the Co addition to 26.6 wt.%. A new strategy to break the trade-off between strength and ductility is proposed [...] Read more.

The addition of Co to Ni-based alloys can reduce the stacking fault energy. In this study, a novel Ni-26.6Co-18.4Cr-4.1Mo-2.3Al-0.3Ti-5.4Nb alloy was developed by increasing the Co addition to 26.6 wt.%. A new strategy to break the trade-off between strength and ductility is proposed by introducing dense nanosized precipitations, stacking faults, and nanoscale twins in the as-prepared alloys. The typical characteristics of the deformed alloy include dense dislocations tangles, nanotwins, stacking faults, and Lomer–Cottrell locks. In addition to the pinning effect of the bulky δ precipitates to the grain boundaries, the nanosized γ′ particles with a coherent interface with the matrix show significant precipitation strengthening. As a result, the alloy exhibits a superior combination of yield strength of 1093 MPa and ductility of 29%. At 700 °C, the alloy has a high yield strength of 833 MPa and an ultimate tensile strength of 1024 MPa, while retaining a ductility of 6.3%. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

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12 pages, 5398 KiB

Open AccessArticle

Valley-Dependent Electronic Properties of Metal Monochalcogenides GaX and Janus Ga₂XY (X, Y = S, Se, and Te)

by Junghwan Kim, Yunjae Kim, Dongchul Sung and Suklyun Hong

Nanomaterials 2024, 14(15), 1295; https://doi.org/10.3390/nano14151295 - 31 Jul 2024

Viewed by 1052

Abstract

Two-dimensional (2D) materials have shown outstanding potential for new devices based on their interesting electrical properties beyond conventional 3D materials. In recent years, new concepts such as the valley degree of freedom have been studied to develop valleytronics in hexagonal lattice 2D materials. [...] Read more.

Two-dimensional (2D) materials have shown outstanding potential for new devices based on their interesting electrical properties beyond conventional 3D materials. In recent years, new concepts such as the valley degree of freedom have been studied to develop valleytronics in hexagonal lattice 2D materials. We investigated the valley degree of freedom of GaX and Janus GaXY (X, Y = S, Se, Te). By considering the spin–orbit coupling (SOC) effect in the band structure calculations, we identified the Rashba-type spin splitting in band structures of Janus Ga₂SSe and Ga₂STe. Further, we confirmed that the Zeeman-type spin splitting at the K and K’ valleys of GaX and Janus Ga₂XY show opposite spin contributions. We also calculated the Berry curvatures of GaX and Janus GaXY. In this study, we find that GaX and Janus Ga₂XY have a similar magnitude of Berry curvatures, while having opposite signs at the K and K’ points. In particular, GaTe and Ga₂SeTe have relatively larger Berry curvatures of about 3.98 Å² and 3.41 Å², respectively, than other GaX and Janus Ga₂XY. Full article

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22 pages, 4005 KiB

Open AccessArticle

Chitosan Nanoparticle-Mediated Delivery of Curcumin Suppresses Tumor Growth in Breast Cancer

by Barnalee Mishra, Amit Singh Yadav, Diksha Malhotra, Tandrima Mitra, Simran Sinsinwar, N. N. V. Radharani, Saroj Ranjan Sahoo, Srinivas Patnaik and Gopal C. Kundu

Nanomaterials 2024, 14(15), 1294; https://doi.org/10.3390/nano14151294 - 31 Jul 2024

Viewed by 1588

Abstract

Curcumin is a nutraceutical known to have numerous medicinal effects including anticancer activity. However, due to its poor water solubility and bioavailability, the therapeutic impact of curcumin against cancer, including breast cancer, has been constrained. Encapsulating curcumin into chitosan nanoparticles (CHNPs) is an [...] Read more.

Curcumin is a nutraceutical known to have numerous medicinal effects including anticancer activity. However, due to its poor water solubility and bioavailability, the therapeutic impact of curcumin against cancer, including breast cancer, has been constrained. Encapsulating curcumin into chitosan nanoparticles (CHNPs) is an effective method to increase its bioavailability as well as antitumorigenic activity. In the current study, the effects of curcumin-encapsulated CHNPs (Cur-CHNPs) on cell migration, targeted homing and tumor growth were examined using in vitro and in vivo breast cancer models. Cur-CHNPs possessed a monodispersed nature with long-term colloidal stability, and demonstrated significant inhibition of cell viability in vitro, which was potentiated by 5-Fluorouracil (5-FU). Outcomes of the in vivo imaging studies confirmed effective tumor targeting and retention ability of Cur-CHNPs, thereby suppressing breast tumor growth in mice models. Overall, the results demonstrated that Cur-CHNPs could be an effective candidate drug formulation for management of breast cancer. Full article

(This article belongs to the Topic Nanomaterials and Diseases)

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20 pages, 6531 KiB

Open AccessArticle

Finely Tunable Carbon Nanofiber Catalysts for the Efficient Production of HMF in Biphasic MIBK/H₂O Systems

by Charf Eddine Bounoukta, Cristina Megías-Sayago, Nuria Rendón, Fatima Ammari, Miguel Angel Centeno and Svetlana Ivanova

Nanomaterials 2024, 14(15), 1293; https://doi.org/10.3390/nano14151293 - 31 Jul 2024

Viewed by 939

Abstract

This work proposes catalytic systems for fructose dehydration to 5-hydroxymethylfurfural using a series of functionalized carbon nanofibers. The catalysts were synthesized via finely selected covalent grafting in order to include a variety of functionalities like pure Bronsted acid, tandem Brønsted/Lewis acid, and tandem [...] Read more.

This work proposes catalytic systems for fructose dehydration to 5-hydroxymethylfurfural using a series of functionalized carbon nanofibers. The catalysts were synthesized via finely selected covalent grafting in order to include a variety of functionalities like pure Bronsted acid, tandem Brønsted/Lewis acid, and tandem Lewis acid/Lewis base catalysts. After the characterization and evaluation of acidity strength and the amount of acid centers, the catalyst series was screened and related to the product distribution. The best-performing catalyst was also used to optimize the reaction parameters in order to achieve 5-hydroxymethylfurfural yields rounding at 60% without significant humin formation. Full article

(This article belongs to the Section 2D and Carbon Nanomaterials)

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14 pages, 6481 KiB

Open AccessArticle

Up-Conversion Luminescence and Optical Temperature Sensing Properties of NaLuF₄:Yb³⁺/Ho³⁺ Micron-Sized Crystals at Low Temperature

by Tian Zhang, Zhaojin Wang, Jin Hou, Xinyi Xu, Xin Zhao, Zijie Li and Siyi Di

Nanomaterials 2024, 14(15), 1292; https://doi.org/10.3390/nano14151292 - 31 Jul 2024

Viewed by 1022

Abstract

Non-contact temperature sensors utilising the fluorescence intensity ratio and the unique up-conversion (UC) luminescence of rare-earth ions have numerous benefits; however, their operational temperature range has remained limited. In this study, NaLuF₄:Yb³⁺/Ho³⁺ samples were prepared by the hydrothermal [...] Read more.

Non-contact temperature sensors utilising the fluorescence intensity ratio and the unique up-conversion (UC) luminescence of rare-earth ions have numerous benefits; however, their operational temperature range has remained limited. In this study, NaLuF₄:Yb³⁺/Ho³⁺ samples were prepared by the hydrothermal method. The samples exhibited exceptional UC luminescence properties at low temperatures. The intensity of the green emission (with peak wavelengths of 540 and 546 nm) gradually decreased with increasing temperature, and the green emissions showed a unique change at low temperatures. In addition, we studied the dependence of the UC luminescence intensity on the excitation power and the variation in the decay lifetime with temperature. The experiments revealed excellent luminous performance and significantly enhanced sensitivity at low temperatures; the maximum absolute sensitivity S_a and relative sensitivity S_r of the 540 and 546 nm thermally coupled energy levels were 1.02% and 0.55% K⁻¹, respectively. The potential temperature sensing properties of Yb³⁺/Ho³⁺-co-doped NaLuF₄ makes it suitable for temperature sensing applications at temperatures as low as 30 K. This study offers a novel approach for the advancement of temperature sensing technology at low temperatures. Full article

(This article belongs to the Special Issue Lanthanide-Doped Luminescent Nanomaterials: Design, Synthesis, Optical Properties and Applications)

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34 pages, 8648 KiB

Open AccessReview

Magnetite-Incorporated 1D Carbon Nanostructure Hybrids for Electromagnetic Interference Shielding

by Bayan Kaidar, Aigerim Imash, Gaukhar Smagulova, Aruzhan Keneshbekova, Ramazan Kazhdanbekov, Eleonora Yensep, Doszhan Akalim and Aidos Lesbayev

Nanomaterials 2024, 14(15), 1291; https://doi.org/10.3390/nano14151291 - 31 Jul 2024

Viewed by 1323

Abstract

The increasing reliance on electronic technologies has elevated the urgency of effective electromagnetic interference (EMI) shielding materials. This review explores the development and potential of magnetite-incorporated one-dimensional (1D) carbon nanostructure hybrids, focusing on their unique properties and synthesis methods. By combining magnetite’s magnetic [...] Read more.

The increasing reliance on electronic technologies has elevated the urgency of effective electromagnetic interference (EMI) shielding materials. This review explores the development and potential of magnetite-incorporated one-dimensional (1D) carbon nanostructure hybrids, focusing on their unique properties and synthesis methods. By combining magnetite’s magnetic properties with the electrical conductivity and mechanical strength of carbon nanostructures such as carbon nanotubes (CNTs) and carbon fibers (CFs), these hybrids offer superior EMI shielding performance. Various synthesis techniques, including solvothermal synthesis, in situ growth, and electrostatic self-assembly, are discussed in detail, highlighting their impact on the structure and properties of the resulting composites. This review also addresses the challenges in achieving homogeneous dispersion of nanofillers and the environmental and economic considerations of large-scale production. The hybrid materials’ multifunctionality, including enhanced mechanical strength, thermal stability, and environmental resistance, underscores their suitability for advanced applications in aerospace, electronics, and environmental protection. Future research directions focus on optimizing synthesis processes and exploring new hybrid configurations to further improve electromagnetic properties and practical applicability. Full article

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Nanomaterials, Volume 14, Issue 15 (August-1 2024) – 85 articles

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