Nanomaterials

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12 pages, 3918 KiB

Open AccessArticle

Fabrication of Biomass Derived Pt-Ni Bimetallic Catalyst and Its Selective Hydrogenation for 4-Nitrostyrene

by Siyu Long, Lingyu Zhang, Zhuoyue Liu, Huibin Jiao, Aiwen Lei, Wei Gong and Xianglin Pei

Nanomaterials 2022, 12(17), 2968; https://doi.org/10.3390/nano12172968 - 27 Aug 2022

Cited by 4 | Viewed by 1840

The hydrogenation products of aromatic molecules with reducible groups (such as C=C, NO₂, C=O, etc.) are relatively critical intermediate compounds in fine chemicals, but how to accurately reduce only specific groups is still challenging. In this work, a bimetallic Pt-Ni/Chitin catalyst [...] Read more.

The hydrogenation products of aromatic molecules with reducible groups (such as C=C, NO₂, C=O, etc.) are relatively critical intermediate compounds in fine chemicals, but how to accurately reduce only specific groups is still challenging. In this work, a bimetallic Pt-Ni/Chitin catalyst was prepared for the first time by using renewable biomass resource chitin as support. As the carrier, the chitin was constructed into porous nanofibrous microspheres through the sol-gel strategy, which was favorable for the adhesion of nano-metals and the exchange of reactive substances due to its large surface area, porous structure, and rich functional groups. Then the Pt-Ni/Chitin catalyst was applied to selective hydrogenation with the model substrate of 4-nitrostyrene. As the highly dispersed Pt-Ni NPs with abundant exposed active sites and the synergistic effect of bimetals, the Pt-Ni/Chitin catalyst could efficiently and selectively hydrogenate only NO₂ or C=C with yields of ~99% and TOF of 660 h⁻¹, as well as good stability. This utilization of biomass resources to build catalyst materials would be important for the green and sustainable chemistry. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

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13 pages, 5517 KiB

Open AccessEditor’s ChoiceArticle

Multifunctional Carbon Nanotubes-Reinforced Surlyn Nanocomposites: A Study of Strain-Sensing and Self-Healing Capabilities

by Antonio del Bosque, Rocío Calderón-Villajos, María Sánchez and Alejandro Ureña

Nanomaterials 2022, 12(16), 2878; https://doi.org/10.3390/nano12162878 - 21 Aug 2022

Cited by 4 | Viewed by 2342

Abstract

Multifunctional nanocomposites based on carbon nanotubes (CNT)-reinforced Surlyn, which is a commercial ionomeric polymer, are manufactured by micro-compounding and hot-press processes. Multifunctionality is studied in terms of electromechanical response and self-healing abilities. The strain sensing analysis under tensile conditions shows ultra-high gauge factor [...] Read more.

Multifunctional nanocomposites based on carbon nanotubes (CNT)-reinforced Surlyn, which is a commercial ionomeric polymer, are manufactured by micro-compounding and hot-press processes. Multifunctionality is studied in terms of electromechanical response and self-healing abilities. The strain sensing analysis under tensile conditions shows ultra-high gauge factor (GF) values from 10 to 20 at low strain levels up to 10⁶ at high strain levels, and a decreasing sensitivity as CNT content increases because of the reduction in the tunneling distance between neighboring nanoparticles. The electromechanical response under consecutive tensile cycles demonstrated the robustness of the proposed materials due to the repeatability of both responses. With regard to mechanical properties, the addition of CNT induces a clear increase in Young’s modulus because the nanoparticles enable uniform load distributions. Moreover, self-healing capabilities are improved when 4 and 5 wt.% CNT are introduced because of the synergistic effect of the high thermal conductivity of CNT and their homogeneous distribution, promoting an increase in the thermal conductivity of bulk nanocomposites. Thus, by comparing the measured functionalities, 4 and 5 wt.% CNT-reinforced Surlyn nanocomposites showed a high potential for various applications due to their high degree of multifunctionality. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

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12 pages, 12679 KiB

Open AccessArticle

Acetone and Toluene Gas Sensing by WO₃: Focusing on the Selectivity from First Principle Calculations

by Mario Italo Trioni, Fausto Cargnoni, Stefano Americo, Eleonora Pargoletti, Gian Luca Chiarello and Giuseppe Cappelletti

Nanomaterials 2022, 12(15), 2696; https://doi.org/10.3390/nano12152696 - 5 Aug 2022

Cited by 4 | Viewed by 1740

Abstract

Sensitivity and selectivity are the two major parameters that should be optimized in chemiresistive devices with boosted performances towards Volatile Organic Compounds (VOCs). Notwithstanding a plethora of metal oxides/VOCs combinations that have been investigated so far, a close inspection based on theoretical models [...] Read more.

Sensitivity and selectivity are the two major parameters that should be optimized in chemiresistive devices with boosted performances towards Volatile Organic Compounds (VOCs). Notwithstanding a plethora of metal oxides/VOCs combinations that have been investigated so far, a close inspection based on theoretical models to provide guidelines to enhance sensors features has been scarcely explored. In this work, we measured experimentally the sensor response of a WO₃ chemiresistor towards gaseous acetone and toluene, observing a two orders of magnitude higher signal for the former. In order to gain insight on the observed selectivity, Density Functional Theory was then adopted to elucidate how acetone and toluene molecules adsorption may perturb the electronic structure of WO₃ due to electrostatic interactions with the surface and hybridization with its electronic structure. The results of acetone adsorption suggest the activation of the carbonyl group for reactions, while an overall lower charge redistribution on the surface and the molecule was observed for toluene. This, combined with acetone’s higher binding energy, justifies the difference in the final responses. Notably, the presence of surface oxygen vacancies, characterizing the nanostructure of the oxide, influences the sensing performances. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

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10 pages, 2820 KiB

Open AccessArticle

A Novel Turn-On Fluorescent Sensor Based on Sulfur Quantum Dots and MnO₂ Nanosheet Architectures for Detection of Hydrazine

by Xin Li, Xiaobin Wang, Wei Guo, Feng Luan, Chunyuan Tian, Xuming Zhuang and Lijun Zhao

Nanomaterials 2022, 12(13), 2207; https://doi.org/10.3390/nano12132207 - 27 Jun 2022

Cited by 2 | Viewed by 1979

Abstract

In this paper, the SQDs@MnO₂ NS as the probe was applied to construct a novel “turn-on” fluorescent sensor for sensitive and selective detection of hydrazine (N₂H₄). Sulfur quantum dots (SQDs) and MnO₂ nanosheets (MnO₂ NS) were [...] Read more.

In this paper, the SQDs@MnO₂ NS as the probe was applied to construct a novel “turn-on” fluorescent sensor for sensitive and selective detection of hydrazine (N₂H₄). Sulfur quantum dots (SQDs) and MnO₂ nanosheets (MnO₂ NS) were simply mixed, through the process of adsorption to prepare the architectures of SQDs@MnO₂ NS. The fluorescent emissions of SQDs@MnO₂ NS play a key role to indicate the state of the sensor. According to the inner filter effect (IFE) mechanism, the state of the sensor at the “off” position, or low emission, under the presence of MnO₂ NS, is which the ultraviolet and visible spectrum overlaps with the fluorescence emission spectrum of SQDs. Under the optimal conditions, the emission was gradually recovered with the addition of the N₂H₄, since the N₂H₄ as a strong reductant could make the MnO₂ NS converted into Mn²⁺, the state of the sensor at the “on”. Meanwhile, the fluorescent sensor possesses good selectivity and high sensitivity, and the detection concentration of N₂H₄ with a wide range from 0.1 µM to 10 mM with a detection limit of 0.072 µM. Furthermore, actual samples were successful in detecting certain implications, indicating that the fluorescent sensor possesses the potential application ability to monitor the N₂H₄ in the water. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

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11 pages, 1609 KiB

Open AccessArticle

Understanding the CH₄ Conversion over Metal Dimers from First Principles

by Haihong Meng, Bing Han, Fengyu Li, Jingxiang Zhao and Zhongfang Chen

Nanomaterials 2022, 12(9), 1518; https://doi.org/10.3390/nano12091518 - 29 Apr 2022

Cited by 2 | Viewed by 1944

Abstract

Inspired by the advantages of bi-atom catalysts and recent exciting progresses of nanozymes, by means of density functional theory (DFT) computations, we explored the potential of metal dimers embedded in phthalocyanine monolayers (M₂-Pc), which mimics the binuclear centers of methane monooxygenase, [...] Read more.

Inspired by the advantages of bi-atom catalysts and recent exciting progresses of nanozymes, by means of density functional theory (DFT) computations, we explored the potential of metal dimers embedded in phthalocyanine monolayers (M₂-Pc), which mimics the binuclear centers of methane monooxygenase, as catalysts for methane conversion using H₂O₂ as an oxidant. In total, 26 transition metal (from group IB to VIIIB) and four main group metal (M = Al, Ga, Sn and Bi) dimers were considered, and two methane conversion routes, namely *O-assisted and *OH-assisted mechanisms were systematically studied. The results show that methane conversion proceeds via an *OH-assisted mechanism on the Ti₂-Pc, Zr₂-Pc and Ta₂-Pc, a combination of *O- and *OH-assisted mechanism on the surface of Sc₂-Pc, respectively. Our theoretical work may provide impetus to developing new catalysts for methane conversion and help stimulate further studies on metal dimer catalysts for other catalytic reactions. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

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13 pages, 4679 KiB

Open AccessArticle

The Effect of Surface Hydroxyls on the Humidity-Sensitive Properties of LiCl-Doped ZnSn(OH)₆ Sphere-Based Sensors

by Zhenjiang Li, Min Zhang, Linyu Yang, Rong Wu, Zhaofeng Wu, Youquan Jiang, Lina Zhou and Yanan Liu

Nanomaterials 2022, 12(3), 467; https://doi.org/10.3390/nano12030467 - 28 Jan 2022

Cited by 8 | Viewed by 2491

Abstract

Pure zinc hydroxystannate (ZnSn(OH)₆) and LiCl-doped ZnSn(OH)₆ have been synthesized through a facile wet chemical method. The LiCl-doped samples keep their original spherical morphology as pure ZnSn(OH)_6, with some LiCl particles stuck to its surface, providing more active sites [...] Read more.

Pure zinc hydroxystannate (ZnSn(OH)₆) and LiCl-doped ZnSn(OH)₆ have been synthesized through a facile wet chemical method. The LiCl-doped samples keep their original spherical morphology as pure ZnSn(OH)_6, with some LiCl particles stuck to its surface, providing more active sites for the adsorption and desorption of water molecules. The influence of LiCl doping on the humidity-sensing properties was explored by varying the dopant concentration. The 16 wt% LiCl/ZnSn(OH)₆ showed a better humidity-sensing performance than that of the pure ZnSn(OH)₆ and other doped samples, including a high resistive sensitivity, a relatively small hysteresis, and a fast response speed. Through the FTIR analysis, the number of hydroxyl groups on the surface structure after aging has been found to decline markedly. These hydroxyl groups provide a platform for the adsorption of water molecules on the surface and promote the dissociation of water molecules. The detriment of aging to sensor performance should not be underrated. The complex impedance spectrum explains the mechanism of the sensor. These results demonstrate that ZnSn(OH)₆ has potential application in fabricating humidity sensors, and the sensing performance of the sensor is enhanced by the dopant LiCl. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

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15 pages, 4330 KiB

Open AccessArticle

Highly Sensitive RNA-Based Electrochemical Aptasensor for the Determination of C-Reactive Protein Using Carbon Nanofiber-Chitosan Modified Screen-Printed Electrode

by Mahmoud Amouzadeh Tabrizi and Pablo Acedo

Nanomaterials 2022, 12(3), 415; https://doi.org/10.3390/nano12030415 - 27 Jan 2022

Cited by 21 | Viewed by 3061

Abstract

C-reactive protein (CRP) is one of the biomarkers related to coronavirus disease 2019 (COVID-19). Therefore, it is crucial to develop a highly sensitive, selective, and cost-effective biosensor for the determination of CRP. In this study, we designed an electrochemical aptasensor. For this purpose, [...] Read more.

C-reactive protein (CRP) is one of the biomarkers related to coronavirus disease 2019 (COVID-19). Therefore, it is crucial to develop a highly sensitive, selective, and cost-effective biosensor for the determination of CRP. In this study, we designed an electrochemical aptasensor. For this purpose, the surface of a carbon screen-printed electrode was first modified with a carbon nanofiber-chitosan (CNFs-CHIT) nanocomposite. After that, the amino-terminal RNA aptamer probes were linked to the amino groups of CHIT via glutaraldehyde as the cross-linker. Finally, methylene blue (MB) as a redox probe was self-assembled on the surface of the aptasensor. The obtained results indicated that the CNFs-CHIT nanocomposite increased the surface coverage of the aptamer up to 5.9 times. The square-wave voltammetry was used for the measurement of CRP concentration in the linear range of 1.0–150.0 pM. The obtained results indicated that the signal had a logarithmic relationship with the concentration of CRP. The limit of detection (LOD) was obtained to be 0.37 pM. The dissociation constant (K_d) that demonstrates the affinity of the aptamer probe to its target was found to be 0.93 pM. The analytical performances of the proposed RNA aptasensor were better than the previously reported aptasensors for CRP. The proposed aptasensor was also applied for the determination of CRP in the human plasma samples. The obtained results indicated that there were no statistically significant differences between the responses of the proposed RNA aptasensor and an enzyme-linked immunosorbent assay kit (ELISA). The analytical performances of the proposed RNA aptasensor described in this paper are better than previously reported aptasensors for CRP determination. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

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11 pages, 1067 KiB

Open AccessArticle

In Situ Ruthenium Catalyst Modification for the Conversion of Furfural to 1,2-Pentanediol

by Lauriane Bruna, Miquel Cardona-Farreny, Vincent Colliere, Karine Philippot and M. Rosa Axet

Nanomaterials 2022, 12(3), 328; https://doi.org/10.3390/nano12030328 - 20 Jan 2022

Cited by 9 | Viewed by 5799

Abstract

Exploiting biomass to synthesise compounds that may replace fossil-based ones is of high interest in order to reduce dependence on non-renewable resources. 1,2-pentanediol and 1,5-pentanediol can be produced from furfural, furfuryl alcohol or tetrahydrofurfuryl alcohol following a metal catalysed hydrogenation/C-O cleavage procedure. Colloidal [...] Read more.

Exploiting biomass to synthesise compounds that may replace fossil-based ones is of high interest in order to reduce dependence on non-renewable resources. 1,2-pentanediol and 1,5-pentanediol can be produced from furfural, furfuryl alcohol or tetrahydrofurfuryl alcohol following a metal catalysed hydrogenation/C-O cleavage procedure. Colloidal ruthenium nanoparticles stabilized with polyvinylpyrrolidone in situ modified with different organic compounds are able to produce 1,2-pentanediol directly from furfural in a 36% of selectivity at 125 °C under 20 bar of H₂ pressure. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

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13 pages, 3083 KiB

Open AccessArticle

An 8 MeV Electron Beam Modified In:ZnO Thin Films for CO Gas Sensing towards Low Concentration

by Aninamol Ani, P. Poornesh, Albin Antony, K. K. Nagaraja, Ashok Rao, Gopalkrishna Hegde, Evgeny Kolesnikov, Igor V. Shchetinin, Suresh D. Kulkarni, Vikash Chandra Petwal, Vijay Pal Verma and Jishnu Dwivedi

Nanomaterials 2021, 11(11), 3151; https://doi.org/10.3390/nano11113151 - 22 Nov 2021

Cited by 5 | Viewed by 2438

Abstract

In the present investigation, electron beam-influenced modifications on the CO gas sensing properties of indium doped ZnO (IZO) thin films were reported. Dose rates of 5, 10, and 15 kGy were irradiated to the IZO nano films while maintaining the In doping concentration [...] Read more.

In the present investigation, electron beam-influenced modifications on the CO gas sensing properties of indium doped ZnO (IZO) thin films were reported. Dose rates of 5, 10, and 15 kGy were irradiated to the IZO nano films while maintaining the In doping concentration to be 15 wt%. The wurtzite structure of IZO films is observed from XRD studies post electron beam irradiation, confirming structural stability, even in the intense radiation environment. The surface morphological studies by SEM confirms the granular structure with distinct and sharp grain boundaries for 5 kGy and 10 kGy irradiated films whereas the IZO film irradiated at 15 kGy shows the deterioration of defined grains. The presence of defects viz oxygen vacancies, interstitials are recorded from room temperature photoluminescence (RTPL) studies. The CO gas sensing estimations were executed at an optimized operating temperature of 300 °C for 1 ppm, 2 ppm, 3 ppm, 4 ppm, and 5 ppm. The 10 kGy treated IZO film displayed an enhanced sensor response of 2.61 towards low concentrations of 1 ppm and 4.35 towards 5 ppm. The enhancement in sensor response after irradiation is assigned to the growth in oxygen vacancies and well-defined grain boundaries since the former and latter act as vital adsorption locations for the CO gas. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

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15 pages, 5121 KiB

Open AccessEditor’s ChoiceArticle

Pd-C Catalytic Thin Films Prepared by Magnetron Sputtering for the Decomposition of Formic Acid

by Gisela Mariana Arzac, Asunción Fernández, Vanda Godinho, Dirk Hufschmidt, Maria Carmen Jiménez de Haro, Beatriz Medrán and Olga Montes

Nanomaterials 2021, 11(9), 2326; https://doi.org/10.3390/nano11092326 - 7 Sep 2021

Cited by 4 | Viewed by 2846

Abstract

Formic acid is an advantageous liquid organic hydrogen carrier. It is relatively nontoxic and can be synthesized by the reaction of CO₂ with sustainable hydrogen or by biomass decomposition. As an alternative to more widely studied powdery catalysts, supported Pd-C catalytic thin [...] Read more.

Formic acid is an advantageous liquid organic hydrogen carrier. It is relatively nontoxic and can be synthesized by the reaction of CO₂ with sustainable hydrogen or by biomass decomposition. As an alternative to more widely studied powdery catalysts, supported Pd-C catalytic thin films with controlled nanostructure and compositions were newly prepared in this work by magnetron sputtering on structured supports and tested for the formic acid decomposition reaction. A two-magnetron configuration (carbon and tailored Pd-C targets) was used to achieve a reduction in Pd consumption and high catalyst surface roughness and dispersion by increasing the carbon content. Activity and durability tests were carried out for the gas phase formic acid decomposition reaction on SiC foam monoliths coated with the Pd-C films and the effects of column width, surface roughness and thermal pre-reduction time were investigated. Activity of 5.04 mol_H2·g_Pd⁻¹·h⁻¹ and 92% selectivity to the dehydrogenation reaction were achieved at 300 °C for the catalyst with a lower column width and higher carbon content and surface roughness. It was also found that deactivation occurs when Pd is sintered due to the elimination of carbon and/or the segregation and agglomeration of Pd upon cycling. Magnetron sputtering deposition appears as a promising and scalable route for the one-step preparation of Pd-C catalytic films by overcoming the different deposition characteristics of Pd and C with an appropriate experimental design. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

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14 pages, 3512 KiB

Open AccessArticle

Vibration Control of Diamond Nanothreads by Lattice Defect Introduction for Application in Nanomechanical Sensors

by Xiao-Wen Lei, Kazuki Bando and Jin-Xing Shi

Nanomaterials 2021, 11(9), 2241; https://doi.org/10.3390/nano11092241 - 30 Aug 2021

Cited by 4 | Viewed by 2557

Abstract

Carbon nanomaterials, such as carbon nanotubes (CNTs) and graphene sheets (GSs), have been adopted as resonators in vibration-based nanomechanical sensors because of their extremely high stiffness and small size. Diamond nanothreads (DNTs) are a new class of one-dimensional carbon nanomaterials with extraordinary physical [...] Read more.

Carbon nanomaterials, such as carbon nanotubes (CNTs) and graphene sheets (GSs), have been adopted as resonators in vibration-based nanomechanical sensors because of their extremely high stiffness and small size. Diamond nanothreads (DNTs) are a new class of one-dimensional carbon nanomaterials with extraordinary physical and chemical properties. Their structures are similar to that of diamond in that they possess

{sp}^{3}

-bonds formed by a covalent interaction between multiple benzene molecules. In this study, we focus on investigating the mechanical properties and vibration behaviors of DNTs with and without lattice defects and examine the influence of density and configuration of lattice defects on the two them in detail, using the molecular dynamics method and a continuum mechanics approach. We find that Young’s modulus and the natural frequency can be controlled by alternating the density of the lattice defects. Furthermore, we investigate and explore the use of DNTs as resonators in nanosensors. It is shown that applying an additional extremely small mass or strain to all types of DNTs significantly changes their resonance frequencies. The results show that, similar to CNTs and GSs, DNTs have potential application as resonators in nano-mass and nano-strain sensors. In particular, the vibration behaviors of DNT resonators can be controlled by alternating the density of the lattice defects to achieve the best sensitivities. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

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22 pages, 8255 KiB

Open AccessArticle

Self-Assembled Ag Nanocomposites into Ultra-Sensitive and Reproducible Large-Area SERS-Active Opaque Substrates

by Abeer Fahes, Aotmane En Naciri, Mohammad Navvabpour, Safi Jradi and Suzanna Akil

Nanomaterials 2021, 11(8), 2055; https://doi.org/10.3390/nano11082055 - 12 Aug 2021

Cited by 13 | Viewed by 2623

Abstract

This work describes a novel, one-shot strategy to fabricate ultrasensitive SERS sensors based on silver/poly(methyl methacrylate) (PMMA) nanocomposites. Upon spin coating of a dispersion of PMMA and silver precursor on N-doped silicon substrate, closely separated silver nanoparticles were self-assembled into uniform nanospheres. As [...] Read more.

This work describes a novel, one-shot strategy to fabricate ultrasensitive SERS sensors based on silver/poly(methyl methacrylate) (PMMA) nanocomposites. Upon spin coating of a dispersion of PMMA and silver precursor on N-doped silicon substrate, closely separated silver nanoparticles were self-assembled into uniform nanospheres. As a result, a thin hydrophobic PMMA layer embedded with Ag nanoparticles (AgNPs) was obtained on the whole silicon substrate. Consequently, a large-scale, reproducible SERS platform was produced through a rapid, simple, low-cost, and high-throughput technology. In addition, reproducible SERS features and high SERS enhancement factors were determined (SEF ~10¹⁵). This finding matches the highest SEF reported in literature to date (10¹⁴) for silver aggregates. The potential and novelty of this synthesis is that no reducing agent or copolymer was used, nor was any preliminary functionalization of the surface carried out. In addition, the AgNPs were fabricated directly on the substrate’s surface; consequently, there was no need for polymer etching. Then, the synthetic method was successfully applied to prepare opaque SERS platforms. Opaque surfaces are needed in photonic devices because of the absence of secondary back reflection, which makes optical analysis and applications easier. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

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18 pages, 5493 KiB

Open AccessEditor’s ChoiceArticle

Advanced Large-Scale Nanofabrication Route for Ultrasensitive SERS Platforms Based on Precisely Shaped Gold Nanostructures

by Suzanna Akil, Rana Omar, Dmitry Kuznetsov, Vladimir Shur, Aotmane En Naciri and Safi Jradi

Nanomaterials 2021, 11(7), 1806; https://doi.org/10.3390/nano11071806 - 12 Jul 2021

Cited by 5 | Viewed by 2414

Abstract

One of the key issues for SERS-based trace applications is engineering structurally uniform substrates with ultrasensitivity, stability, and good reproducibility. A label-free, cost-effective, and reproducible fabrication strategy of ultrasensitive SERS sensors was reported in this work. Herein, we present recent progress in self-assembly-based [...] Read more.

One of the key issues for SERS-based trace applications is engineering structurally uniform substrates with ultrasensitivity, stability, and good reproducibility. A label-free, cost-effective, and reproducible fabrication strategy of ultrasensitive SERS sensors was reported in this work. Herein, we present recent progress in self-assembly-based synthesis to elaborate precisely shaped and abundant gold nanoparticles in a large area. We demonstrated that shape control is driven by the selective adsorption of a cation (Na⁺, K⁺, and H⁺) on a single facet of gold nanocrystal seeds during the growth process. We studied SERS features as a function of morphology. Importantly, we found a correlation between the shape and experimental SERS enhancement factors. We observed a detection threshold of 10⁻²⁰ M of bipyridine ethylene (BPE), which matches the lowest value determined in literature for BPE until now. Such novel sensing finding could be very promising for diseases and pathogen detection and opens up an avenue toward predicting which other morphologies could offer improved sensitivity. Full article

(This article belongs to the Special Issue Nanostructures for Surfaces, Catalysis and Sensing)

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