A novel WO3-x/TiO2 film as photoanode was synthesized for photoelectrocatalytic（PEC） reduction of CO2 into formic acid（HCOOH）. The films prepared by doctor blade method were characterized with X-ray diffractometer...A novel WO3-x/TiO2 film as photoanode was synthesized for photoelectrocatalytic（PEC） reduction of CO2 into formic acid（HCOOH）. The films prepared by doctor blade method were characterized with X-ray diffractometer（XRD）, scanning electron microscope（SEM） and transmission electron microscope（TEM）. The existence of oxygen vacancies in the WO3-x was confirmed with an X-ray photoelectron spectroscopy（XPS）, and the accurate oxygen index was determined by a modified potentiometric titrimetry method. After 3h of photoelectrocatalytic reduction, the formic acid yield of the WO3-x/TiO2 film is 872 nmol/cm^2, which is 1.83 times that of the WO3/TiO2 film. The results of PEC performance demonstrate that the introduction of WO3-x nanoparticles can improve the charge transfer performance so as to enhance the performance of PEC reduction of CO2 into formic acid.展开更多
We report the performances of a chalcopyrite Cu(In, Ga)Se<sub>2 </sub>CIGS-based thin-film solar cell with a newly employed high conductive n-Si layer. The data analysis was performed with the help of the ...We report the performances of a chalcopyrite Cu(In, Ga)Se<sub>2 </sub>CIGS-based thin-film solar cell with a newly employed high conductive n-Si layer. The data analysis was performed with the help of the 1D-Solar Cell Capacitance Simulator (1D-SCAPS) software program. The new device structure is based on the CIGS layer as the absorber layer, n-Si as the high conductive layer, i-In<sub>2</sub>S<sub>3</sub>, and i-ZnO as the buffer and window layers, respectively. The optimum CIGS bandgap was determined first and used to simulate and analyze the cell performance throughout the experiment. This analysis revealed that the absorber layer’s optimum bandgap value has to be 1.4 eV to achieve maximum efficiency of 22.57%. Subsequently, output solar cell parameters were analyzed as a function of CIGS layer thickness, defect density, and the operating temperature with an optimized n-Si layer. The newly modeled device has a p-CIGS/n-Si/In<sub>2</sub>S<sub>3</sub>/Al-ZnO structure. The main objective was to improve the overall cell performance while optimizing the thickness of absorber layers, defect density, bandgap, and operating temperature with the newly employed optimized n-Si layer. The increase of absorber layer thickness from 0.2 - 2 µm showed an upward trend in the cell’s performance, while the increase of defect density and operating temperature showed a downward trend in solar cell performance. This study illustrates that the proposed cell structure shows higher cell performances and can be fabricated on the lab-scale and industrial levels.展开更多
As essential electrochromic（EC） materials are related to energy savings in fenestration technology,tungsten oxide（WO3） films have been intensively studied recently.In order to achieve better understanding of the m...As essential electrochromic（EC） materials are related to energy savings in fenestration technology,tungsten oxide（WO3） films have been intensively studied recently.In order to achieve better understanding of the mechanism of EC properties,and thus facilitate optimization of device performance,clarification of the correlation between cation storage and transfer properties and the coloration performance is needed.In this study,transparent polycrystalline and amorphous WO3 thin films were deposited on SnO2：F-coated glass substrates by the pulsed laser deposition technique.Investigation into optical transmittance in a wavelength range of 400-800 nm measured at a current density of 130 μA·cm-2 with the applied potential ranging from 3.2 to 2.2 V indicates that polycrystalline films have a larger optical modulation of ～ 30% at 600 nm and a larger coloration switch time of 95 s in the whole wavelength range compared with amorphous films（～ 24% and 50 s）.Meanwhile,under the same conditions,polycrystalline films show a larger lithium storage capacity corresponding to a Li/W ratio of 0.5,a smaller lithium diffusion coefficient（2×10-12cm2·s-1 for Li/W=0.24） compared with the amorphous ones,which have a Li/W ratio of 0.29 and a coefficient of ～2.5×10-11cm2·s-1 as Li/W=0.24.These results demonstrate that the large optical modulation relates to the large lithium storage capacity,and the fast coloration transition is associated with fast lithium diffusion.展开更多
Here we report the WO3 thin films on F-doped SnO2 conducting glass (FTO) substrates which were prepared by using dip film-drawing method. Dip film-drawing was a simple, convenient, economical method and in largescale ...Here we report the WO3 thin films on F-doped SnO2 conducting glass (FTO) substrates which were prepared by using dip film-drawing method. Dip film-drawing was a simple, convenient, economical method and in largescale to prepare photoanodes for future applications. The FTO substrates were dipped in tungstic acid solution then film-drawn included 3, 6, 9, 12 and 15 times for prepared different thicknesses of WO3 thin film photoanodes. Then the photoa no des were employed as the electrodes in photoelectrochemical property Keywords: WO3 thin films Dip film-drawing Photoelectrochemical Thicknesses Large-scale measurements, which include scan linear sweep, repeated on/off illumination cycles, electrochemical impedanee spectroscopy and incident phot on to current conversion efficiency, respectively. The results showed that the WO3 thin films dipped 9 times with 175 nm thicknesses had the best photoelectrochemical performance of 0.067 mA·cm^-2 at 1.23 V versus RHE.展开更多
Titanium dioxide （TiO2） loaded tungsten trioxide （WO3） composite films are prepared by an E-beam vapor system. Associated with the existence of a heterojunction at the interface of TiO2 and WO3, the prepared TiO2-...Titanium dioxide （TiO2） loaded tungsten trioxide （WO3） composite films are prepared by an E-beam vapor system. Associated with the existence of a heterojunction at the interface of TiO2 and WO3, the prepared TiO2-WO3 composite film shows enhanced photocurrent density, four times than the pure WO3 film illuminated under xenon lamp, and higher incident-photon-to-current conversion e^ciency. By varying the initial TiO2 film thickness, such composite structures could be optimized to obtain the highest photocurrent density. We believe that thin TiO2 films improve the light response and increase the surface roughness of WO3 films. Furthermore, the existence of the heterojunction results in the e^cient charge carriers＇ separation, transfer process, and a lower recombination of electron-hole pairs, which is beneficial for the enhancement of photocurrent density.展开更多
Normal photocatalysts cannot effectively remove low-concentration NO because of the high recombination rate of the photogenerated carriers.To overcome this problem,S-scheme composites have been developed to fabricate ...Normal photocatalysts cannot effectively remove low-concentration NO because of the high recombination rate of the photogenerated carriers.To overcome this problem,S-scheme composites have been developed to fabricate photocatalysts.Herein,a novel S-scheme Sb2WO6/g-C3N4 nanocomposite was fabricated by an ultrasound-assisted method,which exhibited excellent performance for photocatalytic ppb-level NO removal.Compared with the pure constituents of the nanocomposite,the as-prepared 15%-Sb2WO6/g-C3N4 photocatalyst could remove more than 68%continuous-flowing NO(initial concentration:400 ppb)under visible-light irradiation in 30 min.The findings of the trapping experiments confirmed that•O2^–and h+were the important active species in the NO oxidation reaction.Meanwhile,the transient photocurrent response and PL spectroscopy analyses proved that the unique S-scheme structure of the samples could enhance the charge separation efficiency.In situ DRIFTS revealed that the photocatalytic reaction pathway of NO removal over the Sb2WO6/g-C3N4 nanocomposite occurred via an oxygen-induced route.The present work proposes a new concept for fabricating efficient photocatalysts for photocatalytic ppb-level NO oxidation and provides deeper insights into the mechanism of photocatalytic NO oxidation.展开更多
Pure WOand Yb:WOthin films have been synthesized by spray pyrolysis technique. Effect of Yb doping concentration on photoelectrochemical, structural, morphological and optical properties of thin films are studied. X-r...Pure WOand Yb:WOthin films have been synthesized by spray pyrolysis technique. Effect of Yb doping concentration on photoelectrochemical, structural, morphological and optical properties of thin films are studied. X-ray diffraction analysis shows that all thin films are polycrystalline nature and exhibit monoclinic crystal structure. The 3 at% Yb:WOfilm shows superior photoelectrochemical（PEC） performance than that of pure WOfilm and it shows maximum photocurrent density（Iph= 1090 μA/cm） having onset potentials around +0.3 V/SCE in 0.01 M HClO. The photoelectrocatalytic process is more effective than that of the photocatalytic process for degradation of methyl orange（MO） dye. Yb doping in WOphotocatalyst is greatly effective to degrade MO dye. The enhancement in photoelectrocatalytic activity is mainly due to the suppressing the recombination rate of photogenerated electron-hole pairs. The mineralization of MO dye in aqueous solution is studied by measuring chemical oxygen demand（COD） values.展开更多
Bi_2WO_6 was modified by two-dimensional g-C_3N_4(2D g-C_3N_4)via a hydrothermal method.The structure,morphology,optical and electronic properties were investigated by multiple techniques,including X-ray diffraction(X...Bi_2WO_6 was modified by two-dimensional g-C_3N_4(2D g-C_3N_4)via a hydrothermal method.The structure,morphology,optical and electronic properties were investigated by multiple techniques,including X-ray diffraction(XRD),X-ray photoelectron spectroscopy spectra(XPS),Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Ultravioletvisible diffuse reflection spectroscopy(DRS),photocurrent and electrochemical impedance spectroscopy(EIS),electron spin resonance(ESR),respectively.Rhodamine B(Rh B)was used as the target organic pollutant to research the photocatalytic performance of as-prepared composites.The Bi_2WO_6/2D g-C_3N_4exhibited a remarkable improvement compared with the pure Bi_2WO_6.The enhanced photocatalytic activity was because the photogenerated electrons and holes can quickly separate by Z-Scheme passageway in composites.The photocatalytic mechanism was also researched in detail through ESR analysis.展开更多
The polycrystalline phase WO_3/g-C_3N_4 was synthesized under stirring using tungstenic acid(H_2WO_4) and graphitic carbon nitride(g-C_3N_4) as raw materials. The catalyst was characterized by X-ray diffraction(XRD), ...The polycrystalline phase WO_3/g-C_3N_4 was synthesized under stirring using tungstenic acid(H_2WO_4) and graphitic carbon nitride(g-C_3N_4) as raw materials. The catalyst was characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),the Fourier transform infrared spectroscopy(FT-IR),and the Brunauer-Emmett-Teller analysis(BET). The polycrystalline phase WO_3/g-C_3N_4 was determined by XRD technique. The oxidative desulfurization process was investigated using WO_3/g-C_3N_4 as the catalyst, 30% hydrogen peroxide(H202) as the oxidant, and 1-butyl-3-methylimidazolium tetrafluoroborate([bmim]BF4) ionic liquids(ILs) as the extractant. The operating conditions, including H_2WO_4 amount, IL dose, H_2 O_2 volume, temperature, catalyst dosage, and types of sulfur compounds,were systematically researched. The desulfurization rate could reach 98.46% for removing dibenzothiophene(DBT) from the model oil under optimal reaction conditions. In addition, the catalytic activity was slightly decreased after five recycles of catalysts. The reaction kinetics analysis shows that the oxidative desulfurization system was in accord with the first-order reaction kinetics equation. The mechanism of oxidative desulfurization was proposed.展开更多
基金Project(21471054)supported by the National Natural Science Foundation of China
文摘A novel WO3-x/TiO2 film as photoanode was synthesized for photoelectrocatalytic（PEC） reduction of CO2 into formic acid（HCOOH）. The films prepared by doctor blade method were characterized with X-ray diffractometer（XRD）, scanning electron microscope（SEM） and transmission electron microscope（TEM）. The existence of oxygen vacancies in the WO3-x was confirmed with an X-ray photoelectron spectroscopy（XPS）, and the accurate oxygen index was determined by a modified potentiometric titrimetry method. After 3h of photoelectrocatalytic reduction, the formic acid yield of the WO3-x/TiO2 film is 872 nmol/cm^2, which is 1.83 times that of the WO3/TiO2 film. The results of PEC performance demonstrate that the introduction of WO3-x nanoparticles can improve the charge transfer performance so as to enhance the performance of PEC reduction of CO2 into formic acid.
文摘We report the performances of a chalcopyrite Cu(In, Ga)Se<sub>2 </sub>CIGS-based thin-film solar cell with a newly employed high conductive n-Si layer. The data analysis was performed with the help of the 1D-Solar Cell Capacitance Simulator (1D-SCAPS) software program. The new device structure is based on the CIGS layer as the absorber layer, n-Si as the high conductive layer, i-In<sub>2</sub>S<sub>3</sub>, and i-ZnO as the buffer and window layers, respectively. The optimum CIGS bandgap was determined first and used to simulate and analyze the cell performance throughout the experiment. This analysis revealed that the absorber layer’s optimum bandgap value has to be 1.4 eV to achieve maximum efficiency of 22.57%. Subsequently, output solar cell parameters were analyzed as a function of CIGS layer thickness, defect density, and the operating temperature with an optimized n-Si layer. The newly modeled device has a p-CIGS/n-Si/In<sub>2</sub>S<sub>3</sub>/Al-ZnO structure. The main objective was to improve the overall cell performance while optimizing the thickness of absorber layers, defect density, bandgap, and operating temperature with the newly employed optimized n-Si layer. The increase of absorber layer thickness from 0.2 - 2 µm showed an upward trend in the cell’s performance, while the increase of defect density and operating temperature showed a downward trend in solar cell performance. This study illustrates that the proposed cell structure shows higher cell performances and can be fabricated on the lab-scale and industrial levels.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10979069)the "Hundred Talent Program" of Chinese Academy of Sciences
文摘As essential electrochromic（EC） materials are related to energy savings in fenestration technology,tungsten oxide（WO3） films have been intensively studied recently.In order to achieve better understanding of the mechanism of EC properties,and thus facilitate optimization of device performance,clarification of the correlation between cation storage and transfer properties and the coloration performance is needed.In this study,transparent polycrystalline and amorphous WO3 thin films were deposited on SnO2：F-coated glass substrates by the pulsed laser deposition technique.Investigation into optical transmittance in a wavelength range of 400-800 nm measured at a current density of 130 μA·cm-2 with the applied potential ranging from 3.2 to 2.2 V indicates that polycrystalline films have a larger optical modulation of ～ 30% at 600 nm and a larger coloration switch time of 95 s in the whole wavelength range compared with amorphous films（～ 24% and 50 s）.Meanwhile,under the same conditions,polycrystalline films show a larger lithium storage capacity corresponding to a Li/W ratio of 0.5,a smaller lithium diffusion coefficient（2×10-12cm2·s-1 for Li/W=0.24） compared with the amorphous ones,which have a Li/W ratio of 0.29 and a coefficient of ～2.5×10-11cm2·s-1 as Li/W=0.24.These results demonstrate that the large optical modulation relates to the large lithium storage capacity,and the fast coloration transition is associated with fast lithium diffusion.
基金Supported by the National Natural Science Foundation of China(21522603,21477050,21401082,21503142,21671083)Six Talent Peaks Project in Jiangsu Province(XCL-025)+2 种基金and the Chinese-German Cooperation Research Project(GZ1091)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX17_1774)the Excellent Youth Foundation of Jiangsu Scientific Committee(BK20170526)
文摘Here we report the WO3 thin films on F-doped SnO2 conducting glass (FTO) substrates which were prepared by using dip film-drawing method. Dip film-drawing was a simple, convenient, economical method and in largescale to prepare photoanodes for future applications. The FTO substrates were dipped in tungstic acid solution then film-drawn included 3, 6, 9, 12 and 15 times for prepared different thicknesses of WO3 thin film photoanodes. Then the photoa no des were employed as the electrodes in photoelectrochemical property Keywords: WO3 thin films Dip film-drawing Photoelectrochemical Thicknesses Large-scale measurements, which include scan linear sweep, repeated on/off illumination cycles, electrochemical impedanee spectroscopy and incident phot on to current conversion efficiency, respectively. The results showed that the WO3 thin films dipped 9 times with 175 nm thicknesses had the best photoelectrochemical performance of 0.067 mA·cm^-2 at 1.23 V versus RHE.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11174137,11474215 and 21204058the Natural Science Foundation for the Youth of Jiangsu Province under Grant No BK20130284the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Titanium dioxide （TiO2） loaded tungsten trioxide （WO3） composite films are prepared by an E-beam vapor system. Associated with the existence of a heterojunction at the interface of TiO2 and WO3, the prepared TiO2-WO3 composite film shows enhanced photocurrent density, four times than the pure WO3 film illuminated under xenon lamp, and higher incident-photon-to-current conversion e^ciency. By varying the initial TiO2 film thickness, such composite structures could be optimized to obtain the highest photocurrent density. We believe that thin TiO2 films improve the light response and increase the surface roughness of WO3 films. Furthermore, the existence of the heterojunction results in the e^cient charge carriers＇ separation, transfer process, and a lower recombination of electron-hole pairs, which is beneficial for the enhancement of photocurrent density.
文摘Normal photocatalysts cannot effectively remove low-concentration NO because of the high recombination rate of the photogenerated carriers.To overcome this problem,S-scheme composites have been developed to fabricate photocatalysts.Herein,a novel S-scheme Sb2WO6/g-C3N4 nanocomposite was fabricated by an ultrasound-assisted method,which exhibited excellent performance for photocatalytic ppb-level NO removal.Compared with the pure constituents of the nanocomposite,the as-prepared 15%-Sb2WO6/g-C3N4 photocatalyst could remove more than 68%continuous-flowing NO(initial concentration:400 ppb)under visible-light irradiation in 30 min.The findings of the trapping experiments confirmed that•O2^–and h+were the important active species in the NO oxidation reaction.Meanwhile,the transient photocurrent response and PL spectroscopy analyses proved that the unique S-scheme structure of the samples could enhance the charge separation efficiency.In situ DRIFTS revealed that the photocatalytic reaction pathway of NO removal over the Sb2WO6/g-C3N4 nanocomposite occurred via an oxygen-induced route.The present work proposes a new concept for fabricating efficient photocatalysts for photocatalytic ppb-level NO oxidation and provides deeper insights into the mechanism of photocatalytic NO oxidation.
基金University Grants Commission(UGC),New Delhi,for the financial support through the project No.‘‘41-869/2012(SR)’’
文摘Pure WOand Yb:WOthin films have been synthesized by spray pyrolysis technique. Effect of Yb doping concentration on photoelectrochemical, structural, morphological and optical properties of thin films are studied. X-ray diffraction analysis shows that all thin films are polycrystalline nature and exhibit monoclinic crystal structure. The 3 at% Yb:WOfilm shows superior photoelectrochemical（PEC） performance than that of pure WOfilm and it shows maximum photocurrent density（Iph= 1090 μA/cm） having onset potentials around +0.3 V/SCE in 0.01 M HClO. The photoelectrocatalytic process is more effective than that of the photocatalytic process for degradation of methyl orange（MO） dye. Yb doping in WOphotocatalyst is greatly effective to degrade MO dye. The enhancement in photoelectrocatalytic activity is mainly due to the suppressing the recombination rate of photogenerated electron-hole pairs. The mineralization of MO dye in aqueous solution is studied by measuring chemical oxygen demand（COD） values.
基金supported by National Nature Science Foundation of China (21476097, 21776118)Six talent peaks project in Jiangsu Province (2014-JNHB-014)Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Bi_2WO_6 was modified by two-dimensional g-C_3N_4(2D g-C_3N_4)via a hydrothermal method.The structure,morphology,optical and electronic properties were investigated by multiple techniques,including X-ray diffraction(XRD),X-ray photoelectron spectroscopy spectra(XPS),Fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Ultravioletvisible diffuse reflection spectroscopy(DRS),photocurrent and electrochemical impedance spectroscopy(EIS),electron spin resonance(ESR),respectively.Rhodamine B(Rh B)was used as the target organic pollutant to research the photocatalytic performance of as-prepared composites.The Bi_2WO_6/2D g-C_3N_4exhibited a remarkable improvement compared with the pure Bi_2WO_6.The enhanced photocatalytic activity was because the photogenerated electrons and holes can quickly separate by Z-Scheme passageway in composites.The photocatalytic mechanism was also researched in detail through ESR analysis.
基金the financial support of the Doctoral Fund of Liaoning Province (201501105)
文摘The polycrystalline phase WO_3/g-C_3N_4 was synthesized under stirring using tungstenic acid(H_2WO_4) and graphitic carbon nitride(g-C_3N_4) as raw materials. The catalyst was characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),the Fourier transform infrared spectroscopy(FT-IR),and the Brunauer-Emmett-Teller analysis(BET). The polycrystalline phase WO_3/g-C_3N_4 was determined by XRD technique. The oxidative desulfurization process was investigated using WO_3/g-C_3N_4 as the catalyst, 30% hydrogen peroxide(H202) as the oxidant, and 1-butyl-3-methylimidazolium tetrafluoroborate([bmim]BF4) ionic liquids(ILs) as the extractant. The operating conditions, including H_2WO_4 amount, IL dose, H_2 O_2 volume, temperature, catalyst dosage, and types of sulfur compounds,were systematically researched. The desulfurization rate could reach 98.46% for removing dibenzothiophene(DBT) from the model oil under optimal reaction conditions. In addition, the catalytic activity was slightly decreased after five recycles of catalysts. The reaction kinetics analysis shows that the oxidative desulfurization system was in accord with the first-order reaction kinetics equation. The mechanism of oxidative desulfurization was proposed.
