Density functional theory calculations were used to unravel the mechanism of CO_2 electroreduction on SnO_x surfaces. Under highly reducing conditions(<-0.6 V vs. RHE), the SnO(101) surface with oxygen vacancies is...Density functional theory calculations were used to unravel the mechanism of CO_2 electroreduction on SnO_x surfaces. Under highly reducing conditions(<-0.6 V vs. RHE), the SnO(101) surface with oxygen vacancies is likely the active phase for CO_2 reduction. We showed that the proton-electron transfer to adsorbed *CO_2 forming *OCHO, a key intermediate for producing HCOOH, is energetically more favorable than the formation of *COOH, justifying the selectivity trends observed on Sn-based electrocatalysts. With linear scaling relations, we propose the free formation energy of *CO_2 at the oxygen vacancy as the reactivity descriptor. By engineering the strain of the SnO(101) surface, the selectivity towards HCOOH can be further optimized at reduced overpotentials.展开更多
Photoelectrocatalytic(PEC)materials for harvesting solar energy can be discovered from existing photocatalytic semiconductors.Nonetheless,mixed valence tin oxides,a group of widely reported visible light active photoc...Photoelectrocatalytic(PEC)materials for harvesting solar energy can be discovered from existing photocatalytic semiconductors.Nonetheless,mixed valence tin oxides,a group of widely reported visible light active photocatalysts,can hardly be developed into efficient PEC photoelectrodes.To overcome this difficulty by clarifying its origin,two typical mixed valence tin oxides,Sn^(2+):SnO_(2) microrods and porous Sn_(3)O_(4) particles were deliberately prepared as the models.Sn^(2+):SnO_(2) microrods of less porosity exhibited a photocurrent over ten times higher than Sn_(3)O_(4) particles.Photo-electrochemical impedance spectroscopy revealed this was due to their charge kinetics difference,specifically the internal transport/-transfer responding to the morphology.Moreover,hydroxyl residuals from synthesis were found to be very inhibitive for the PEC efficiency as well,which was in coherence with our TGA and Raman spectroscopic study.These finding experimentally proved the necessity of reconsidering the surface area,crystallinity,and defects when developing photocatalysts into efficient PEC structures.展开更多
Defect engineering,especially oxygen vacancies(O-vacancies) introduction into metal oxide materials has been proved to be an effective strategy to manipulate their surface electron exchange processes.However,quantitat...Defect engineering,especially oxygen vacancies(O-vacancies) introduction into metal oxide materials has been proved to be an effective strategy to manipulate their surface electron exchange processes.However,quantitative investigation of O-vacancies on CO2 electroreduction still remains rather ambiguous.Herein,a series of nanoporous tin oxide(SnOx) materials have been prepared by thermal treatment at various temperatures and reaction conditions.The annealing temperature dependent Ovacancies property of the SnOx was revealed and attributed to the balance tunning of the desorption of oxygen species and the continous oxidation of SnOx.The as-prepared nanoporous SnOx with 300℃treatment was found to be highest O-vacant material and showed an impressive CO2 RR activity and selectivity towards the conversion of CO2 into formic acid(up to 88.6%),and superior HCOOH incomplete current density to other samples.The ideal performance of the O-vacancies rich SnOx-300 material can be ascribed to the high delocalized electron density inducing much enhanced adsorption of CO2 with O binding and benefiting the subsequent reduction with high selectively forming of formic acid.展开更多
Transparent conducting aluminum doped tin oxide thin films were prepared by sol-gel dip coating method with differ-ent Al concentrations and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV-...Transparent conducting aluminum doped tin oxide thin films were prepared by sol-gel dip coating method with differ-ent Al concentrations and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV-Vis spectrophotometry and photoconductivity study. The variation observed in the properties of the measured films agrees with a difference in the film's thickness, which decreases when Al concentration augments. X-ray diffraction analysis reveals that all films are polycrystal-line with tetragonal structure, (110) plane being the strongest diffraction peak. The crystallite size calculated by the Debye Scher-rer’s formula decreases from 11.92 to 8.54 nm when Al concentration increases from 0 to 5 wt.%. AFM images showed grains uni-formly distributed in the deposited films. An average transmittance greater than 80% was measured for the films and an en-ergy gap value of about 3.9 eV was deduced from the optical analysis. Finally, the photosensitivity properties like current-voltage characteristics, ION/IOFF ratio, growth and decay time are studied and reported. Also, we have calculated the trap depth energy using the decay portion of the rise and decay curve photocurrent.展开更多
Proton exchange membrane(PEM)water electrolysis represents a promising technology for green hydrogen production,but its widespread deployment is greatly hindered by the indispensable usage of platinum group metal cata...Proton exchange membrane(PEM)water electrolysis represents a promising technology for green hydrogen production,but its widespread deployment is greatly hindered by the indispensable usage of platinum group metal catalysts,especially iridium(Ir)based materials for the energy-demanding oxygen evolution reaction(OER).Herein,we report a new sequential precipitation approach to the synthesis of mixed Ir-nickel(Ni)oxy-hydroxide supported on antimony-doped tin oxide(ATO)nanoparticles(IrNiyO_(x)/ATO,20 wt.%(Ir+Ni),y=0,1,2,and 3),aiming to reduce the utilisation of scarce and precious Ir while maintaining its good acidic OER performance.When tested in strongly acidic electrolyte(0.1 M HClO_(4)),the optimised IrNi1Ox/ATO shows a mass activity of 1.0 mAµgIr^(−1) and a large turnover frequency of 123 s^(−1) at an overpotential of 350 mV,as well as a comparatively small Tafel slope of 50 mV dec^(−1),better than the IrOx/ATO control,particularly with a markedly reduced Ir loading of only 19.7µgIr cm^(−2).Importantly,IrNi1O_(x)/ATO also exhibits substantially better catalytic stability than other reference catalysts,able to continuously catalyse acidic OER at 10 mA cm^(−2) for 15 h without obvious degradation.Our in-situ synchrotron-based x-ray absorption spectroscopy confirmed that the Ir^(3+)/Ir^(4+)species are the active sites for the acidic OER.Furthermore,the performance of IrNi1Ox/ATO was also preliminarily evaluated in a membrane electrode assembly,which shows better activity and stability than other reference catalysts.The IrNi1Ox/ATO reported in this work is a promising alternative to commercial IrO_(2) based catalysts for PEM electrolysis.展开更多
The present work mainly describes the technology for preparing indium-tin oxide (ITO) targets by cold isostatic pressing (CIP) and normal pressure sintering process. ITO powders were produced by chemical co-precip...The present work mainly describes the technology for preparing indium-tin oxide (ITO) targets by cold isostatic pressing (CIP) and normal pressure sintering process. ITO powders were produced by chemical co-precipitation and shaped into an ITO green compact with a relative density of 60% by CIP under 300 MPa. Then, an ITO target with a relative density larger than 99.6% was obtained by sintering this green compact at 1550℃ for 8 h. The effects of forming pressure, sintering temperature and sintering time on the density of the target were inves- tigated. Also, a discussion was made on the sintering atmosphere.展开更多
Silver tin oxide composite powders were synthesized by the hydrothermal method with a silver ammine solution and a Na2SnO3 solution as raw materials. H2C2O4 was used as the co-precipitator of silver ions and tin ions....Silver tin oxide composite powders were synthesized by the hydrothermal method with a silver ammine solution and a Na2SnO3 solution as raw materials. H2C2O4 was used as the co-precipitator of silver ions and tin ions. The co-precipitation conditions were investigated. The results show that the co-precipitate of Ag2C2O4 and Sn(OH)4 is available when the pH value of the solution is 4.27-8.36. Using the obtained precipitate as precursor,the reduction of Ag+ and the crystallization of tin oxide were carried out simultaneously by the hydrothermal method and silver tin oxide composite powders were obtained. The composite powders were characterized by X-ray diffraction (XRD) analysis,scanning electron microscope (SEM),and energy spectrum analysis. The results show that the silver tin oxide composite powders are small with a diameter of about 2 μm and with homogeneous distribution of tin.展开更多
The lossy nature of indium tin oxide(ITO) at epsilon-near-zero(ENZ) wavelength is used to design an electrically tunable metasurface absorber. The metasurface unit cell is constructed of a circular resonator comprisin...The lossy nature of indium tin oxide(ITO) at epsilon-near-zero(ENZ) wavelength is used to design an electrically tunable metasurface absorber. The metasurface unit cell is constructed of a circular resonator comprising two ITO discs and a high dielectric constant perovskite barium strontium titanate(BST) film. The ENZ wavelength in the accumulation and depletion layers of ITO discs is controlled by applying a single bias voltage. The coupling of magnetic dipole resonance with the ENZ wavelength inside the accumulation layer of ITO film causes total absorption of reflected light. The reflection amplitude can achieve ~84 d B or ~99.99% modulation depth in the operation wavelength of 820 nm at a bias voltage of-2.5 V. Moreover, the metasurface is insensitive to the polarization of the incident light due to the circular design of resonators and the symmetrical design of bias connections.展开更多
Tin/tin oxide materials are key electrocatalysts for selective conversion of CO;to formate/formic acid.Herein we report a tin oxide material with nitrogen doping by using ammonia treatment at elevated temperature. The...Tin/tin oxide materials are key electrocatalysts for selective conversion of CO;to formate/formic acid.Herein we report a tin oxide material with nitrogen doping by using ammonia treatment at elevated temperature. The N doped material demonstrated enhanced electrocatalytic CO;reduction activity, showing high Faradaic efficiency(90%) for formate at -0.65 V vs. RHE with partial current density of 4 mA/cm;.The catalysis was contributed to increased electron negativity of N atom compared to O atom. Additionally, the N-doped catalyst demonstrates sulfur tolerance with retained formate selectivity. The analysis after electrolysis shows that the catalyst structure partially converts to metallic Sn, and thus the combined Sn/N-SnO;is the key for the active CO;catalysis.展开更多
Antimony-doped tin hydroxide colloid precipitates have been synthesized by hydrolysis of SnCl4 and SbCl3 using: (1) an ion-exchange hydrolysis to remove chlorine ions, and (2) isoamyl acetate as an azeotropic sol...Antimony-doped tin hydroxide colloid precipitates have been synthesized by hydrolysis of SnCl4 and SbCl3 using: (1) an ion-exchange hydrolysis to remove chlorine ions, and (2) isoamyl acetate as an azeotropic solvent to obviate water. The obtained dried powder is of high dispersivity without any need for further grinding. The size and dispersivity of the final particles are investigated with the aid of TG-DTA, BET, XRD and TEM. After having calcined, the antimony-doped tin oxide nanopowder possesses a tetragonal rutile structure with high dispersivity, uniform particles and low hard agglomeration.展开更多
This study aims to systematically analyze the key parameters of the reflow process that influence the uniformity of the chromium passivation film coated on tinplate. The distribution characteristics of the chromium pa...This study aims to systematically analyze the key parameters of the reflow process that influence the uniformity of the chromium passivation film coated on tinplate. The distribution characteristics of the chromium passivation film coated on the tinplate surface under different treatment conditions were systematically characterized using the scanning Kelvin probe technique, X-ray photoelectron spectroscopy, and X-ray diffraction. Results indicate that the use of flux reduces the porosity of tin coating, thereby favoring the uniform growth of the passivation film. Furthermore, an increase in the reflow power and quenching temperature facilitates the homogeneous distribution of the passivation film on the tinplate surface,particularly when treated with electrolytic cathodic sodium dichromate.展开更多
A SnO-graphite composite material, which can deliver high capacities and good cycling stability compared with unsupported SnO, was described. This material prepared via chemical co-precipitation reaction in the presen...A SnO-graphite composite material, which can deliver high capacities and good cycling stability compared with unsupported SnO, was described. This material prepared via chemical co-precipitation reaction in the presence of graphite consists of high dispersion of SnO with a size of about several hundred nanometers in the graphite. The phase structure was analyzed by X-ray diffraction (XRD). The morphology and the element distribution were examined by scanning electron microscopy (SEM) equipped with energy spectrum. The results show that the SnO-graphite composites produced by slowly hydrolysis have higher rechargeable capacities than pure graphite and better cycling performance than SnO.展开更多
The emergence of hybrid organic-inorganic metal halide perovskite solar cells (PSCs) causes a break through in the solar technology recently due to its fabrication processes. The dramatic enhancenlent in in 2009 to ...The emergence of hybrid organic-inorganic metal halide perovskite solar cells (PSCs) causes a break through in the solar technology recently due to its fabrication processes. The dramatic enhancenlent in in 2009 to the recent certified record PCE of 22.7% superior optoelectronic properties and the low-cost power conversion efficiency (PCE) of PSCs flom 3.8% ndicates huge potential of PSCs for future high efficiency and large scale photovoltaic manufacturing. The electron selective layer (ESL) plays an important role in electron extraction and hole blocking function in PSCs, and there have been great interest in developing efficient ESL materials. Recently, tin oxide (SnO2) as an ESL has attracted significant research attentions owing to its low temperature preparation processes as well as yielding high PCE and good stability of PSCs. In this perspective article, we focus on the development progress of SnO2 as an ESL m PSCs, and discuss the strategies for preparing SnO2 to achieve PSCs with high efficiency, less hysteresis and good device stability.展开更多
Raw scrap powders containing 10 wt.% In were recovered by sand-blasting chamber shields of sputter coaters and used as a sole source of indium components for both sieving and air-classification. Sieving was performed ...Raw scrap powders containing 10 wt.% In were recovered by sand-blasting chamber shields of sputter coaters and used as a sole source of indium components for both sieving and air-classification. Sieving was performed first as a feasibility test, and enrichment of indium component was possible up to 19 wt.% with a mesh size of 635. With this experimental basis, the raw scrap powders were air-classified into 12 lots according to the revolution per minute (r/min) of a single horizontally arranged classifying wheel: 4000, 6000, 8000, 10000, 12000, and 14000 r/rain. The particle cut size varied from 56 to 5 μm with turbo wheel speeds corresponding to 4000 to 14000 r/min, respectively, and enrichment of indium component was possible in fine overflow fractions at all turbo wheel speeds while the indium components were not concentrated in all of the coarse underflow fractions. The grade of the indium components became higher with decreasing particle size of the air-classified scrap powders, with the highest grade obtained in the fine overflow fraction with a turbo wheel speed of 14000 r/min. The amount of indium in the fine overflow fractions varied between 15.9 wt.% and 31.5 wt.%. All in all, the grade or purity of the indium component improved rather significantly from 15.9 wt.% to 31.5 wt.% by air-classification, but this also resulted in overall decrease in recovery rate from 99.33% to 49.64%. Therefore, enrichment and separation of indium should be optimized for maximum recovery and grade of the indium components, which can be used as raw materials in the subsequent electro-refining processes.展开更多
Indium tin oxide(ITO)thin films(100±10nm)were deposited on PC(polycarbonate)and glass substrates by rf(radio-frequency)mannetron spuutering.The oxygen content of the ITO films was changed by variation of ...Indium tin oxide(ITO)thin films(100±10nm)were deposited on PC(polycarbonate)and glass substrates by rf(radio-frequency)mannetron spuutering.The oxygen content of the ITO films was changed by variation of the sputtering gas composition.All the other deposition parameters were kept constant.The sheet resistance.optical transmittance and microstructure of ITO films were investigated using a four-point probe.spectrophotometer,X-ray diffractometer(XRD)and atomic force microscope(AFM).Sheet resistances for the ITO films with optical transmittance more than 75% on PC substrates varied from 40Ω/cm^2 to more than 104 Ω/cm^2 with increasing oxygen partial pressure from O to about 2%.The same tendeney of sheet resistances increasing with increasing oxygen partial pressure was observed on glass substrates.The X-ray diffraction data indicated polycrystalline filns with grain orientations predominantly along(440)and (422)directions.The intensities of (440)and (422)peaks increased slightly with the increase of oxygen partial pressure both on PC and glass substrates.The AFM images show that the ITO films on PC substrates were dense and uniform.The average grain size of the films was about 40nm.展开更多
Annealing effect on the performance of fully transparent thin-film transistor (TTFT), in which zinc tin oxide (ZnSnO) is used as the channel material and SiO2 as the gate insulator, is investigated. The ZnSnO acti...Annealing effect on the performance of fully transparent thin-film transistor (TTFT), in which zinc tin oxide (ZnSnO) is used as the channel material and SiO2 as the gate insulator, is investigated. The ZnSnO active layer is deposited by radio frequency magnetron sputtering while a SiO2 gate insulator is formed by plasma-enhanced chemical vapor deposition. The saturation field-effect mobility and on/off ratio of the TTFT are improved by low temperature annealing in vacuum. Maximum saturation field-effect mobility and on/off ratio of 56.2 cm2/(V.s) and 3×10^5 are obtained, respectively. The transfer characteristics of the ZnSnO TPT are simulated using an analytical model and good agreement between measured and the calculated transfer characteristics is demonstrated.展开更多
The electrical and optical properties of the indium tin oxide (ITO)/epoxy composite exhibit dramatic variations as functions of the ITO composition and ITO particle size. Sharp increases in the conductivity in the v...The electrical and optical properties of the indium tin oxide (ITO)/epoxy composite exhibit dramatic variations as functions of the ITO composition and ITO particle size. Sharp increases in the conductivity in the vicinity of a critical volume fraction have been found within the framework of percolation theory. A conductive and insulating transition model is extracted by the ITO particle network in the SEM image, and verified by the resistivity dependence on the temperature. The dependence of the optical transmittance on the particle size was studied. Further decreasing the ITO particle size could further improve the percolation threshold and light transparency of the composite film.展开更多
A modified polyacrylamide gel route is applied to synthesize SnO2 nanoparticles. High-quality SnO2 nanoparticles with a uniform size are prepared using different chelating agents. The average particle size of the samp...A modified polyacrylamide gel route is applied to synthesize SnO2 nanoparticles. High-quality SnO2 nanoparticles with a uniform size are prepared using different chelating agents. The average particle size of the samples is found to depend on the choice of the chelating agent. The photoluminescence spectrum detected at λex = 230 nm shows a new peak located at 740 nm due to the surface defect level distributed at the nanoparticle boundaries.展开更多
Nanostructured tin dioxide (SnO2) powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method.The thick film sensors were fabricated from th...Nanostructured tin dioxide (SnO2) powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method.The thick film sensors were fabricated from the CuO/SnO2 polycrystalline powders.Sensing behavior of the sensor was investigated with various gases including CO,H2,NH3,hexane,acetone,ethanol,methanol and H2S in air.The as-synthesized gas sensor had much better response to H2S than to other gases.At the same time,the CuO/SnO2 sensor had enough sensitivity,together with fast response and recovery,to distinguish H2S from those gases at 160 and 210 ℃.Therefore,it might have promising applications in the future.展开更多
Tin oxide(SnO2) and fluorine doped tin oxide(FTO) films were prepared on glass substrates by sol-gel spin-coating using SnCl4 and NH4F precursors.Fluorine doping concentration was fixed at 4 at%and 20 at%by contro...Tin oxide(SnO2) and fluorine doped tin oxide(FTO) films were prepared on glass substrates by sol-gel spin-coating using SnCl4 and NH4F precursors.Fluorine doping concentration was fixed at 4 at%and 20 at%by controlling precursor sol composition.Films exhibited the tetragonal rutile-type crystal structure regardless of fluorine concentration.Uniform and highly transparent FTO films,with more than 85%of optical transmittance,were obtained by annealing at 600℃.Florine doping of films was verified by analyzing the valence band region obtained by XPS.It was found that the fluorine doping affects the shape of valence band of SnO2 films.In addition,it was observed that the band gap of SnO2 is reduced as well as the Fermi level is upward shifted by the effect of fluorine doping.展开更多
基金financial support from the American Chemical Society Petroleum Research Fund (ACS PRF 55581-DNI5)the Institute for Critical Technology and Applied Science (ICTAS-J0663175)the NSF CBET Catalysis and Biocatalysis Program (CBET-1604984)
文摘Density functional theory calculations were used to unravel the mechanism of CO_2 electroreduction on SnO_x surfaces. Under highly reducing conditions(<-0.6 V vs. RHE), the SnO(101) surface with oxygen vacancies is likely the active phase for CO_2 reduction. We showed that the proton-electron transfer to adsorbed *CO_2 forming *OCHO, a key intermediate for producing HCOOH, is energetically more favorable than the formation of *COOH, justifying the selectivity trends observed on Sn-based electrocatalysts. With linear scaling relations, we propose the free formation energy of *CO_2 at the oxygen vacancy as the reactivity descriptor. By engineering the strain of the SnO(101) surface, the selectivity towards HCOOH can be further optimized at reduced overpotentials.
基金support by the National Natural Science Foundation of China(NSFC,Grant Nos.21805298,21905288,51904288)K.C.Wong Education Foundation(GJTD-2019-13)+1 种基金Ningbo major special projects of the Plan"Science and Technology Innovation 2025"(No.2018B10056,No.2019B10046)Ningbo 3315 Program。
文摘Photoelectrocatalytic(PEC)materials for harvesting solar energy can be discovered from existing photocatalytic semiconductors.Nonetheless,mixed valence tin oxides,a group of widely reported visible light active photocatalysts,can hardly be developed into efficient PEC photoelectrodes.To overcome this difficulty by clarifying its origin,two typical mixed valence tin oxides,Sn^(2+):SnO_(2) microrods and porous Sn_(3)O_(4) particles were deliberately prepared as the models.Sn^(2+):SnO_(2) microrods of less porosity exhibited a photocurrent over ten times higher than Sn_(3)O_(4) particles.Photo-electrochemical impedance spectroscopy revealed this was due to their charge kinetics difference,specifically the internal transport/-transfer responding to the morphology.Moreover,hydroxyl residuals from synthesis were found to be very inhibitive for the PEC efficiency as well,which was in coherence with our TGA and Raman spectroscopic study.These finding experimentally proved the necessity of reconsidering the surface area,crystallinity,and defects when developing photocatalysts into efficient PEC structures.
基金supported by the National Natural Science Foundation of China,National Key Research and Development Project (No.2016YFF0204402)the Program for Changjiang Scholars and Innovative Research Team in the University+1 种基金the Fundamental Research Funds for the Central Universitiesthe longterm subsidy mechanism from the Ministry of Finance and the Ministry of Education of PRC
文摘Defect engineering,especially oxygen vacancies(O-vacancies) introduction into metal oxide materials has been proved to be an effective strategy to manipulate their surface electron exchange processes.However,quantitative investigation of O-vacancies on CO2 electroreduction still remains rather ambiguous.Herein,a series of nanoporous tin oxide(SnOx) materials have been prepared by thermal treatment at various temperatures and reaction conditions.The annealing temperature dependent Ovacancies property of the SnOx was revealed and attributed to the balance tunning of the desorption of oxygen species and the continous oxidation of SnOx.The as-prepared nanoporous SnOx with 300℃treatment was found to be highest O-vacant material and showed an impressive CO2 RR activity and selectivity towards the conversion of CO2 into formic acid(up to 88.6%),and superior HCOOH incomplete current density to other samples.The ideal performance of the O-vacancies rich SnOx-300 material can be ascribed to the high delocalized electron density inducing much enhanced adsorption of CO2 with O binding and benefiting the subsequent reduction with high selectively forming of formic acid.
基金support of the laboratory of active components and materials,Oum El Bouaghi University.
文摘Transparent conducting aluminum doped tin oxide thin films were prepared by sol-gel dip coating method with differ-ent Al concentrations and characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV-Vis spectrophotometry and photoconductivity study. The variation observed in the properties of the measured films agrees with a difference in the film's thickness, which decreases when Al concentration augments. X-ray diffraction analysis reveals that all films are polycrystal-line with tetragonal structure, (110) plane being the strongest diffraction peak. The crystallite size calculated by the Debye Scher-rer’s formula decreases from 11.92 to 8.54 nm when Al concentration increases from 0 to 5 wt.%. AFM images showed grains uni-formly distributed in the deposited films. An average transmittance greater than 80% was measured for the films and an en-ergy gap value of about 3.9 eV was deduced from the optical analysis. Finally, the photosensitivity properties like current-voltage characteristics, ION/IOFF ratio, growth and decay time are studied and reported. Also, we have calculated the trap depth energy using the decay portion of the rise and decay curve photocurrent.
基金supported by the National Innovation Agency of Portugal through the project Baterias 2030(Grant No.POCI-01-0247-FEDER-046109)J R E would like to acknowledge the Fundación General CSIC’s ComFuturo programme which has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No.101034263+2 种基金The authors appreciate Dr Laura Simonelli and Dr Vlad Martin Diaconescu for their assistance in XAS measurements at the beamline BL22-CLÆSS,ALBA synchrotron(experiment AV-2022025706)R M is grateful to the Portuguese Foundation for Science and Technology(FCT)for the doctoral grant(Grant No.2021.06496.BD)R M and A M are grateful for the financial support from:LA/P/0045/2020,UIDB/00511/2020 and UIDP/00511/2020,funded by the national funds through FCT/MCTES(PIDDAC)。
文摘Proton exchange membrane(PEM)water electrolysis represents a promising technology for green hydrogen production,but its widespread deployment is greatly hindered by the indispensable usage of platinum group metal catalysts,especially iridium(Ir)based materials for the energy-demanding oxygen evolution reaction(OER).Herein,we report a new sequential precipitation approach to the synthesis of mixed Ir-nickel(Ni)oxy-hydroxide supported on antimony-doped tin oxide(ATO)nanoparticles(IrNiyO_(x)/ATO,20 wt.%(Ir+Ni),y=0,1,2,and 3),aiming to reduce the utilisation of scarce and precious Ir while maintaining its good acidic OER performance.When tested in strongly acidic electrolyte(0.1 M HClO_(4)),the optimised IrNi1Ox/ATO shows a mass activity of 1.0 mAµgIr^(−1) and a large turnover frequency of 123 s^(−1) at an overpotential of 350 mV,as well as a comparatively small Tafel slope of 50 mV dec^(−1),better than the IrOx/ATO control,particularly with a markedly reduced Ir loading of only 19.7µgIr cm^(−2).Importantly,IrNi1O_(x)/ATO also exhibits substantially better catalytic stability than other reference catalysts,able to continuously catalyse acidic OER at 10 mA cm^(−2) for 15 h without obvious degradation.Our in-situ synchrotron-based x-ray absorption spectroscopy confirmed that the Ir^(3+)/Ir^(4+)species are the active sites for the acidic OER.Furthermore,the performance of IrNi1Ox/ATO was also preliminarily evaluated in a membrane electrode assembly,which shows better activity and stability than other reference catalysts.The IrNi1Ox/ATO reported in this work is a promising alternative to commercial IrO_(2) based catalysts for PEM electrolysis.
基金supported by the National High-Tech Research and Development Program of China(No. 2004AA303542)
文摘The present work mainly describes the technology for preparing indium-tin oxide (ITO) targets by cold isostatic pressing (CIP) and normal pressure sintering process. ITO powders were produced by chemical co-precipitation and shaped into an ITO green compact with a relative density of 60% by CIP under 300 MPa. Then, an ITO target with a relative density larger than 99.6% was obtained by sintering this green compact at 1550℃ for 8 h. The effects of forming pressure, sintering temperature and sintering time on the density of the target were inves- tigated. Also, a discussion was made on the sintering atmosphere.
文摘Silver tin oxide composite powders were synthesized by the hydrothermal method with a silver ammine solution and a Na2SnO3 solution as raw materials. H2C2O4 was used as the co-precipitator of silver ions and tin ions. The co-precipitation conditions were investigated. The results show that the co-precipitate of Ag2C2O4 and Sn(OH)4 is available when the pH value of the solution is 4.27-8.36. Using the obtained precipitate as precursor,the reduction of Ag+ and the crystallization of tin oxide were carried out simultaneously by the hydrothermal method and silver tin oxide composite powders were obtained. The composite powders were characterized by X-ray diffraction (XRD) analysis,scanning electron microscope (SEM),and energy spectrum analysis. The results show that the silver tin oxide composite powders are small with a diameter of about 2 μm and with homogeneous distribution of tin.
基金supported by the Agency for Science, Technology and Research (A*STAR) under AME IRG Grant No. A2083c0058AME IAF-PP Grant No. 182 24 30030+1 种基金HBMS IAF-PP Grant No. H19H6a0025by MOE Tier 3 program LUNI170919a PUBMOE。
文摘The lossy nature of indium tin oxide(ITO) at epsilon-near-zero(ENZ) wavelength is used to design an electrically tunable metasurface absorber. The metasurface unit cell is constructed of a circular resonator comprising two ITO discs and a high dielectric constant perovskite barium strontium titanate(BST) film. The ENZ wavelength in the accumulation and depletion layers of ITO discs is controlled by applying a single bias voltage. The coupling of magnetic dipole resonance with the ENZ wavelength inside the accumulation layer of ITO film causes total absorption of reflected light. The reflection amplitude can achieve ~84 d B or ~99.99% modulation depth in the operation wavelength of 820 nm at a bias voltage of-2.5 V. Moreover, the metasurface is insensitive to the polarization of the incident light due to the circular design of resonators and the symmetrical design of bias connections.
基金financially supported by Key Research Program of the Chinese Academy of Sciences (ZDRW-ZS-2016-3)the National Key Research and Development Program of China (2016YFB0600901)the Instrument Developing Project of the Chinese Academy of Sciences
文摘Tin/tin oxide materials are key electrocatalysts for selective conversion of CO;to formate/formic acid.Herein we report a tin oxide material with nitrogen doping by using ammonia treatment at elevated temperature. The N doped material demonstrated enhanced electrocatalytic CO;reduction activity, showing high Faradaic efficiency(90%) for formate at -0.65 V vs. RHE with partial current density of 4 mA/cm;.The catalysis was contributed to increased electron negativity of N atom compared to O atom. Additionally, the N-doped catalyst demonstrates sulfur tolerance with retained formate selectivity. The analysis after electrolysis shows that the catalyst structure partially converts to metallic Sn, and thus the combined Sn/N-SnO;is the key for the active CO;catalysis.
基金National Natural Science Foundation of China (50533060)
文摘Antimony-doped tin hydroxide colloid precipitates have been synthesized by hydrolysis of SnCl4 and SbCl3 using: (1) an ion-exchange hydrolysis to remove chlorine ions, and (2) isoamyl acetate as an azeotropic solvent to obviate water. The obtained dried powder is of high dispersivity without any need for further grinding. The size and dispersivity of the final particles are investigated with the aid of TG-DTA, BET, XRD and TEM. After having calcined, the antimony-doped tin oxide nanopowder possesses a tetragonal rutile structure with high dispersivity, uniform particles and low hard agglomeration.
文摘This study aims to systematically analyze the key parameters of the reflow process that influence the uniformity of the chromium passivation film coated on tinplate. The distribution characteristics of the chromium passivation film coated on the tinplate surface under different treatment conditions were systematically characterized using the scanning Kelvin probe technique, X-ray photoelectron spectroscopy, and X-ray diffraction. Results indicate that the use of flux reduces the porosity of tin coating, thereby favoring the uniform growth of the passivation film. Furthermore, an increase in the reflow power and quenching temperature facilitates the homogeneous distribution of the passivation film on the tinplate surface,particularly when treated with electrolytic cathodic sodium dichromate.
文摘A SnO-graphite composite material, which can deliver high capacities and good cycling stability compared with unsupported SnO, was described. This material prepared via chemical co-precipitation reaction in the presence of graphite consists of high dispersion of SnO with a size of about several hundred nanometers in the graphite. The phase structure was analyzed by X-ray diffraction (XRD). The morphology and the element distribution were examined by scanning electron microscopy (SEM) equipped with energy spectrum. The results show that the SnO-graphite composites produced by slowly hydrolysis have higher rechargeable capacities than pure graphite and better cycling performance than SnO.
基金supported by Shenzhen Science and Technology Innovation Commission(Project no.JCYJ20170413154602102)the Project of Strategic Importance provided by Hong Kong Polytechnic University(Project no.1-ZE29)+1 种基金National High Technology Research and Development Program(Project no.2015AA050601)the National Natural Science Foundation of China(Project nos.11674252,61376013,91433203)
文摘The emergence of hybrid organic-inorganic metal halide perovskite solar cells (PSCs) causes a break through in the solar technology recently due to its fabrication processes. The dramatic enhancenlent in in 2009 to the recent certified record PCE of 22.7% superior optoelectronic properties and the low-cost power conversion efficiency (PCE) of PSCs flom 3.8% ndicates huge potential of PSCs for future high efficiency and large scale photovoltaic manufacturing. The electron selective layer (ESL) plays an important role in electron extraction and hole blocking function in PSCs, and there have been great interest in developing efficient ESL materials. Recently, tin oxide (SnO2) as an ESL has attracted significant research attentions owing to its low temperature preparation processes as well as yielding high PCE and good stability of PSCs. In this perspective article, we focus on the development progress of SnO2 as an ESL m PSCs, and discuss the strategies for preparing SnO2 to achieve PSCs with high efficiency, less hysteresis and good device stability.
文摘Raw scrap powders containing 10 wt.% In were recovered by sand-blasting chamber shields of sputter coaters and used as a sole source of indium components for both sieving and air-classification. Sieving was performed first as a feasibility test, and enrichment of indium component was possible up to 19 wt.% with a mesh size of 635. With this experimental basis, the raw scrap powders were air-classified into 12 lots according to the revolution per minute (r/min) of a single horizontally arranged classifying wheel: 4000, 6000, 8000, 10000, 12000, and 14000 r/rain. The particle cut size varied from 56 to 5 μm with turbo wheel speeds corresponding to 4000 to 14000 r/min, respectively, and enrichment of indium component was possible in fine overflow fractions at all turbo wheel speeds while the indium components were not concentrated in all of the coarse underflow fractions. The grade of the indium components became higher with decreasing particle size of the air-classified scrap powders, with the highest grade obtained in the fine overflow fraction with a turbo wheel speed of 14000 r/min. The amount of indium in the fine overflow fractions varied between 15.9 wt.% and 31.5 wt.%. All in all, the grade or purity of the indium component improved rather significantly from 15.9 wt.% to 31.5 wt.% by air-classification, but this also resulted in overall decrease in recovery rate from 99.33% to 49.64%. Therefore, enrichment and separation of indium should be optimized for maximum recovery and grade of the indium components, which can be used as raw materials in the subsequent electro-refining processes.
文摘Indium tin oxide(ITO)thin films(100±10nm)were deposited on PC(polycarbonate)and glass substrates by rf(radio-frequency)mannetron spuutering.The oxygen content of the ITO films was changed by variation of the sputtering gas composition.All the other deposition parameters were kept constant.The sheet resistance.optical transmittance and microstructure of ITO films were investigated using a four-point probe.spectrophotometer,X-ray diffractometer(XRD)and atomic force microscope(AFM).Sheet resistances for the ITO films with optical transmittance more than 75% on PC substrates varied from 40Ω/cm^2 to more than 104 Ω/cm^2 with increasing oxygen partial pressure from O to about 2%.The same tendeney of sheet resistances increasing with increasing oxygen partial pressure was observed on glass substrates.The X-ray diffraction data indicated polycrystalline filns with grain orientations predominantly along(440)and (422)directions.The intensities of (440)and (422)peaks increased slightly with the increase of oxygen partial pressure both on PC and glass substrates.The AFM images show that the ITO films on PC substrates were dense and uniform.The average grain size of the films was about 40nm.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.61290305 and 91021020)the Natural Science Foundation of Zhejiang Province,China (Grant No.Z6100117)
文摘Annealing effect on the performance of fully transparent thin-film transistor (TTFT), in which zinc tin oxide (ZnSnO) is used as the channel material and SiO2 as the gate insulator, is investigated. The ZnSnO active layer is deposited by radio frequency magnetron sputtering while a SiO2 gate insulator is formed by plasma-enhanced chemical vapor deposition. The saturation field-effect mobility and on/off ratio of the TTFT are improved by low temperature annealing in vacuum. Maximum saturation field-effect mobility and on/off ratio of 56.2 cm2/(V.s) and 3×10^5 are obtained, respectively. The transfer characteristics of the ZnSnO TPT are simulated using an analytical model and good agreement between measured and the calculated transfer characteristics is demonstrated.
基金supported by the National Natural Science Foundation of China(Grant Nos.61222501 and 61335004)
文摘The electrical and optical properties of the indium tin oxide (ITO)/epoxy composite exhibit dramatic variations as functions of the ITO composition and ITO particle size. Sharp increases in the conductivity in the vicinity of a critical volume fraction have been found within the framework of percolation theory. A conductive and insulating transition model is extracted by the ITO particle network in the SEM image, and verified by the resistivity dependence on the temperature. The dependence of the optical transmittance on the particle size was studied. Further decreasing the ITO particle size could further improve the percolation threshold and light transparency of the composite film.
基金Project supported by the Joint Fund of the National Natural Science Foundation of China and the China Academy of Engineering Physics (Grant Nos. 11076008 and 61178018)the Ph.D. Programs Foundation of Ministry of Education of China (Grant No. 20110185110007)
文摘A modified polyacrylamide gel route is applied to synthesize SnO2 nanoparticles. High-quality SnO2 nanoparticles with a uniform size are prepared using different chelating agents. The average particle size of the samples is found to depend on the choice of the chelating agent. The photoluminescence spectrum detected at λex = 230 nm shows a new peak located at 740 nm due to the surface defect level distributed at the nanoparticle boundaries.
文摘Nanostructured tin dioxide (SnO2) powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method.The thick film sensors were fabricated from the CuO/SnO2 polycrystalline powders.Sensing behavior of the sensor was investigated with various gases including CO,H2,NH3,hexane,acetone,ethanol,methanol and H2S in air.The as-synthesized gas sensor had much better response to H2S than to other gases.At the same time,the CuO/SnO2 sensor had enough sensitivity,together with fast response and recovery,to distinguish H2S from those gases at 160 and 210 ℃.Therefore,it might have promising applications in the future.
文摘Tin oxide(SnO2) and fluorine doped tin oxide(FTO) films were prepared on glass substrates by sol-gel spin-coating using SnCl4 and NH4F precursors.Fluorine doping concentration was fixed at 4 at%and 20 at%by controlling precursor sol composition.Films exhibited the tetragonal rutile-type crystal structure regardless of fluorine concentration.Uniform and highly transparent FTO films,with more than 85%of optical transmittance,were obtained by annealing at 600℃.Florine doping of films was verified by analyzing the valence band region obtained by XPS.It was found that the fluorine doping affects the shape of valence band of SnO2 films.In addition,it was observed that the band gap of SnO2 is reduced as well as the Fermi level is upward shifted by the effect of fluorine doping.