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Big Potential From Silicon-Based Porous Nanomaterials: In Field of Energy Storage and Sensors
摘要： Silicon nanoparticles (SiNPs) are the promising materials in the various applications due to their unique properties like large surface area, biocompatibility, stability, excellent optical and electrical properties. Surface, optical and electrical properties are highly dependent on particle size, doping of different materials and so on. Porous structures in silicon nanomaterials not only improve the specific surface area, adsorption, and photoluminescence efficiency but also provide numbers of voids as well as the high surface to volume ratio and enhance the adsorption ability. In this review, we focus on the significance of porous silicon/mesoporous silicon nanoparticles (pSiNPs/mSiNPs) in the applications of energy storage, sensors and bioscience. Silicon as anode material in the lithium-ion batteries (LIBs) faces a huge change in volume during charging/discharging which leads to cracking, electrical contact loss and unstable solid electrolyte interphase. To overcome challenges of Si anode in the LIBs, mSiNPs are the promising candidates with different structures and coating of different materials to enhance electrochemical properties. On the basis of optical properties with tunable wavelength, pSiNPs are catching good results in biosensors and gas sensors. The mSiNPs with different structures and modified surfaces are playing an important role in the detection of biomarkers, drug delivery and diagnosis of cancer and tumors.
关键词： lithium ion battery,silicon nanomaterials,bioapplication,porous structures,core shell
更新于2025-09-09 09:28:46
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Highly efficient ethanol gas sensor based on hierarchical SnO2/Zn2SnO4 porous spheres
摘要： In this work, hierarchucal porous SnO2/Zn2SnO4 nanospheres were succesfully prepared via a facile one-step hydrothermal method with subsequent calcination process. Scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were employed in order to investigate the structural and morphological properties of the as-prepared composites. The results showed that the SnO2/Zn2SnO4 composites were cpmposed of many porous nanospheres with a uniform diameter of about 500 nm. Moreover, the as-prepared products were used as sensing material for the fabrication of gas sensor. The sensing performance of the sensor was systematically evaluated, and the sensor exhibited excellent ethanol-sensing property. The optimum operating temperature was 250 oC with a reponse of 30.5 toward 100 ppm ethanol. Also, the sensor showed good selectivity, stability and a low detection limit of 0.5 ppm (response 1.4). The good sensing performance of SnO2/Zn2SnO4 nanospheres can be attibuted to the porous structure as well as the heterojunction formed between SnO2 and ZnSn2O4.
关键词： SnO2/Zn2SnO4,Porous sphere,Hydrothermal method,Ethanol,Gas sensor
更新于2025-09-09 09:28:46
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Tuning the Porosity of TiO2 Nanoparticles via Surfactant-Templated Aerosol Process for Enhanced Photocatalytic Reactivity
摘要： In this work, we fabricated crystallite solid and porous TiO2 nanoparticles (NPs) using a surfactant-templated aerosol process. Specifically, Brij-58 surfactant was employed as a template in TiO2 matrix. The porosity of TiO2 NPs was controlled by varying the amount of Brij-58. The effect of TiO2 porosity on the photocatalytic reactivity was systematically examined. As a result, the highly porous TiO2 NPs exhibited much better photocatalytic reactivity than the low porosity TiO2 NPs. This suggests that the particle size, crystallite structure, and specific surface area play an important role in enhancing the photocatalytic reactivity of the TiO2 NPs.
关键词： surfactants,Aerosol process,photocatalysts,porous TiO2 nanoparticles,specific surface area
更新于2025-09-09 09:28:46
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Structure and Permeability of Porous Silicon Investigated by Self-Diffusion NMR Measurements of Ethanol and Heptane
摘要： The adsorption and phase transitions of con?ned ?uids in nanoporous materials have been studied intensely because of both their fundamental interest and their crucial role in many technologies. Questions relating to the in?uence of the con?nement of ?uids, and the disorder or elastic deformation of porous solids on the liquid-gas phase transition are still under debate. Model systems are needed to understand the adsorption phenomenon. In this context, Porous Silicon (PoSi), which is a single crystal obtained by etching a (100) silicon wafer is an excellent candidate. Indeed, it consists of non-connected tubular pores running parallel to the [100] axis perpendicular to the wafer surface, with transverse sections with a polygonal shape of nanometric size whose areas are widely distributed. Once detached from the wafer, free PoSi membranes can be considered a nanoscale disordered honeycomb. Adsorption/desorption experiments have been performed to characterize the structure: they have shown that evaporation occurs collectively, an intriguing observation generally associated with a disordered pore structure with many interconnections through narrow necks. The characterization of ?uid mobility inside the pores should give complementary information about the pore structure and topology. This paper focuses on the dynamics of a ?uid con?ned inside the structure of porous silicon, and in particular the self-diffusion measurements (pulsed ?eld gradient spin echo Nuclear Magnetic Resonance (NMR)). The results show a strong anisotropy of the self-diffusion tensor, as expected in this highly anisotropic structure. However, a non-zero self-diffusion in the directions perpendicular to the pore axis is observed. In order to interpret these puzzling results, molecular and Brownian dynamics calculations are underway.
关键词： Ethanol,Porous Silicon,Permeability,Heptane,Self-Diffusion NMR
更新于2025-09-09 09:28:46
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UV distributed Bragg reflectors build from porous silicon multilayers
摘要： UV Distributed Bragg reflectors were fabricated by a two-step thermal oxidation process over porous silicon multilayers (PS-ML), which were prepared by room-temperature electrochemical anodization of silicon wafers. The optical behavior of the PS-ML before and after oxidation was studied by reflectance measurements. It was observed an UV shift from 430 to 300 nm in the peak of the reflectance spectrum after oxidation of the PS-ML. This was attributed to the presence of silicon oxide over the surface of the silicon filaments. Such oxide also reduced the refractive index of each porous silicon monolayer. The bandgap of the PS-ML was calculated by the Kubelka-Munk approximation, which showed an increase in the bandgap from 3.11 to 4.36 eV after the thermal oxidation process. It was suggested that the observed optical response could opens the possibility of fabrication of UV optoelectronic devices based entirely in the silicon technology.
关键词： Porous silicon,thermal oxidation,multilayers,ultraviolet (UV)
更新于2025-09-09 09:28:46
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Porous Silicon Bragg Reflector/Carbon Dot Hybrids: Synthesis, Nanostructure, and Optical Properties
摘要： Carbon dots (C-dots) exhibit unique fluorescence properties, mostly depending upon their physical environments. Here we investigate the optical properties and nanostructure of Carbon dots (C-dots) which are synthesized in situ within different porous Silicon (PSi) Bragg reflectors. The resulting hybrids were characterized by photoluminescence, X-ray photoelectron, and Fourier Transform Infrared spectroscopies, as well as by confocal and transmission electron microscopy. We show that by tailoring the location of the PSi Bragg reflector photonic bandgap and its oxidation level, the C-dots emission spectral features can be tuned. Notably, their fluorescence emission can be significantly enhanced when the high reflection band of the PSi host overlaps with the confined C-dots’ peak wavelength, and the PSi matrix is thermally oxidized at mild conditions. These phenomena are observed for multiple compositions of PSi Bragg reflectors/C-dots hybrids.
关键词： optical properties,fluorescence,Fabry–Pérot,Bragg reflectors,porous silicon,photoluminescence,carbon dots
更新于2025-09-09 09:28:46
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Petal-biotemplated synthesis of two-dimensional Co3O4 nanosheets as photocatalyst with enhanced photocatalytic activity
摘要： A biomorphic Co3O4 nanosheet was fabricated by using China rose petal as biotemplate. Ultraviolet-visible diffuse reflectance spectroscopy, nitrogen adsorption, Fourier-transform infrared spectroscopy, thermogravimetric analysis-differential scanning calorimetric analysis, scanning electron microscopy, transmission electron microscopy and powder X-ray diffraction were utilized to characterize the samples. The results revealed that the synthesized Co3O4 sample exhibited the special 2D nanosheet morphology with the thickness of around 100 nm similar to the original petal. The 2D nanosheet structure and multiple-porous feature of the sample not only increased its specific surface area and more active sites for photodegradation reaction, but also facilitated mass transfer, light scattering and harvesting as well as inhibition of the photogenerated carrier recombination. Moreover, compared with the commercial Co3O4, the as-prepared Co3O4 nanosheet showed a superior photocatalytic activity due to its 2D multiple-porous nanosheet structure and high specific surface area (51.36 m2 g?1).
关键词： Petal,Biotemplate,Co3O4 nanosheet,Photocatalysis,Multiple-porous structure
更新于2025-09-09 09:28:46
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Nickel foam–caged Ag-Au bimetallic nanostructure as a highly rugged and durable SERS substrate
摘要： A three-dimensional nickel foam (NF) caging Ag-Au bimetallic nanostructure (Ag-Au@NF) has been demonstrated as a highly rugged and sensitive surface-enhanced Raman scattering (SERS) substrate. The main concept employed in designing this substrate was the protection of SERS-active nanostructures by holding them within a sturdy frame. For this purpose, NF was readily chosen as a strong porous frame to secure the internal nanostructures owing to its excellent structural strength and ability to easily incorporate analytes due to its porous structure. The next issue was the construction of stable and SERS-e?cient nanostructures within the NF frame. To meet this need, an Ag-Au bimetallic nanostructure was chosen, combining the high SERS e?ciency of Ag and the good surface stability of Au. To fabricate the Ag-Au nanostructure, ?rst a Sn-Ag alloy was constructed on the NF frame by means of electrodeposition (producing Sn-Ag@NF) and then Sn was selectively leached from the alloy by means of free corrosion in NaOH solution (producing Ag@NF). This selective leaching was adopted to make the surface rough to enhance the SERS e?ciency in the ?nal substrate. Finally, Au was incorporated into the Ag@NF by means of a galvanic replacement reaction (producing Ag-Au@NF). The use of Ag-Au@NF enabled identi?cation of rhodamine 6G at concentrations as low as 0.1 nM. The Ag-Au@NF substrates were rugged, showing small Raman signal drops after 100 cycles of sandpaper abrasion or 30 min of sonication. Also, the signal decrease was only 4.26% upon 3 days of exposure to ambient air without special care. Overall, the Ag-Au@NF developed herein shows practical merits for adoption in routine and ?eld SERS analyses.
关键词： Surface enhanced Raman scattering,High durability,Ag-Au nanostructure,Porous structure,Nickel foam
更新于2025-09-09 09:28:46
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A Biomedical Surface Enhanced Raman Scattering Substrate: Functionalized Three-Dimensional Porous Membrane Decorated with Silver Nanoparticles
摘要： We fabricated a simple, cheap, and functional surface enhanced Raman scattering substrate for biomedical application. Hotspots between two close silver nanoparticles distributed in the skeleton of a three-dimensional porous membrane, especially in the pores, were formed. The dual poles of micropores in the membrane were discussed. The pores could protect the silver nanoparticles in the pores from being oxidized, which makes the membrane effective for a longer period of time. In addition, Staphylococcus aureus cells could be trapped by the micropores and then the Raman signal became stronger, indicating that the functional surface enhanced Raman scattering substrate is reliable.
关键词： three-dimensional porous membrane,biomedical application,silver nanoparticles,surface enhanced Raman scattering
更新于2025-09-09 09:28:46
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Preparation and Performance of Porous Polymer Electrolytes Doped with Nano-Al <sub/>2</sub> O <sub/>3</sub>
摘要： Porous polymer electrolytes (PPEs) doped with nano-Al2O3 were prepared by a joint application of ultrasonic treatment and control evaporation in vacuum oven. The morphology, pore size distribution, thermal, electrochemical and mechanical properties of the PPEs were investigated. The porosity distribution of PPEs was uniform and their pore size was relatively modest. The total resistance (R t) of PPEs with 10% Al2O3 is only 9 Ω at 80 °C. The maximum tensile strength of the PPEs membranes reached to 24.43 MPa. The results show that nano-Al2O3 can improve the comprehensive performance of PPEs without compromising their conductivity and diplayed the good application prospects of Al2O3-modi?ed PPEs for lithium-ion batteries.
关键词： PEO-PMMA Blends,Nano-Al2O3,Porous Polymer Electrolytes,Interfacial Compatibility,Lithium-Ion Batteries
更新于2025-09-09 09:28:46