Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-dop...Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-doped tin oxide(FTO)glass and employed as the photoanode for photoelectrocatalytic degradation of methylene blue simulated dye wastewater.The Ovsites on the a-Fe_(2)O_(3)-NA surface are the active sites for methylene blue(MB)adsorption.Electrons transfer from the adsorbed MB to Fe-O is detected.Compared with electrocatalytic and photocatalytic degradation processes,the photoelectrocatalytic(PEC)process exhibited the best degrading performance and the largest kinetic constant.Hydroxyl,superoxide free radicals,and photo-generated holes play a jointly leading role in the PEC degradation.A possible degrading pathway is suggested by liquid chromatography-mass spectroscopy analysis.This work demonstrates that photoelectrocatalysis by a-Fe_(2)O_(3)-NA has a remarkable superiority over photocatalysis and electrocatalysis in MB degradation.The in-depth investigation of photoelectrocatalytic degradation mechanism in this study is meaningful for organic wastewater treatment.展开更多
Low optical absorption and photocorrosion are two crucial issues limiting the practical applications of zinc oxide(ZnO)-based photocatalysts.In this paper,we report the fabrication of graphitic-carbon-mediated ZnO nan...Low optical absorption and photocorrosion are two crucial issues limiting the practical applications of zinc oxide(ZnO)-based photocatalysts.In this paper,we report the fabrication of graphitic-carbon-mediated ZnO nanorod arrays(NRAs)with enhanced photocatalytic activity and photostability for CO2 reduction under visible light irradiation.ZnO NRA/C-x(x=005,01,02,and 03)nanohybrids are prepared by calcining pre-synthesized ZnO NRAs with different amounts of glucose(0.05,0.1,0.2,and 0.3 g)as a carbon source via a hydrothermal method.X-ray photoelectron spectroscopy reveals that the obtained ZnO NRA/C-x nanohybrids are imparted with the effects of both carbon doping and carbon coating,as evidenced by the detected C-O-Zn bond and the C-C,C-O and C=O bonds,respectively.While the basic structure of ZnO remains unchanged,the UV-Vis absorption spectra show increased absorbance owing to the carbon doping effect in the ZnO NRA/C-x nanohybrids.The photoluminescence(PL)intensities of ZnO NRA/C-x nanohybrids are lower than that of bare ZnO NRA,indicating that the graphitic carbon layer coated on the surface of the ZnO NRA significantly enhances the charge carrier separation and transport,which in turn enhances the photoelectrochemical property and photocatalytic activity of the ZnO NRA/C-x nanohybrids for CO2 reduction.More importantly,a long-term reaction of photocatalytic CO2 reduction demonstrates that the photostability of ZnO NRA/C-x nanohybrids is significantly increased in comparison with the bare ZnO NRA.展开更多
All-solid-state Z-scheme photocatalysts for overall water splitting to evolve H_(2) is a promising strategy for efficient conversion of solar energy.However,most of these strategies require redox mediators.Herein,a di...All-solid-state Z-scheme photocatalysts for overall water splitting to evolve H_(2) is a promising strategy for efficient conversion of solar energy.However,most of these strategies require redox mediators.Herein,a direct Z-scheme photoelectrocatalytic electrode based on a WO_(3-x)nanowire-bridged TiO_(2)nanorod array heterojunction is constructed for overall water splitting,producing H_(2).The as-prepared WO_(3-x)/TiO_(2)nanorod array heterojunction shows photoelectrochemical(PEC)overall water splitting activity evolving both H_(2) and O_(2)under UV-vis light irradiation.An optimum PEC activity was achieved over a 1.67-WO_(3-x)/TiO_(2)photoelectrode yielding maximum H_(2) and O_(2)evolution rates roughly 11 times higher than that of pure TiO_(2)nanorods without any sacrificial agent or redox mediator.The role of oxygen vacancy in WO_(3-x)in affecting the H_(2) production rate was also comprehensively studied.The superior PEC activity of the WO_(3-x)/TiO_(2)electrode for overall water splitting can be ascribed to an efficient Z-scheme charge transfer pathway between the WO_(3-x)nanowires and TiO_(2)nanorods,the presence of oxygen vacancies in WO_(3-x),and a bias potential applied on the photoelectrode,resulting in effective spatial charge separation.This study provides a novel strategy for developing highly efficient PECs for overall water splitting.展开更多
TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells. Vertically aligned Tit2 nanorod arrays （NRs） are grown on the fluorine-doped tin oxide （FTO） substrates by a multicycle hydr...TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells. Vertically aligned Tit2 nanorod arrays （NRs） are grown on the fluorine-doped tin oxide （FTO） substrates by a multicycle hydrothermal synthesis process. The samples are characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, high-resolution transmission electron microscopy （HRTEM）, and selected-area electron diffraction （SAED）. It is found that dye-sensitized solar cells （DSSCs） assembled by the as-prepared Tit2 single-crystal NRs exhibit different trends under the condition of different nucleation and growth concentrations. Optimum cell performance is obtained with high nucleation concentration and low growth cycle concentration. The efficiency enhancement is mainly attributed to the improved specific surface area of the nanorod.展开更多
CdSe/CdS semiconductor quantum dots co-sensitized TiO2 nanorod array was fabricated on the transparent conductive fluorine-doped tin oxide （FTO） substrate using the hydrothermal and successive ionic layer adsorption...CdSe/CdS semiconductor quantum dots co-sensitized TiO2 nanorod array was fabricated on the transparent conductive fluorine-doped tin oxide （FTO） substrate using the hydrothermal and successive ionic layer adsorption and reaction （SILAR） process. The structural and morphological properties of the samples were characterized by X-ray diffraction （XRD）, field-emission scanning electron microscopy （FESEM）, and transmission electron microscopy （TEM）. The results indicate that CdSe/CdS QDs are uniformly coated on the surface of the TiO2 nanorods. The shift of light absorption edge was monitored by taking UV-visible absorption spectra. Compared with the absorption spectra of the TiO2 nanorod array, deposition of CdSe/CdS QDs shifts the absorption edge to the higher wavelength. The enhanced light absorption in the visible-light region of CdSe/CdS/TiO2 nanorod array indicates that CdSe/CdS layers can act as co-sensitizers in quantum dots sensitized solar cells （QDSSCs）. By optimizing the CdSe layer deposition cycles, a photocurrent of 5.78 mA/cm2, an open circuit photovoltage of 0.469 V and a conversion efficiency of 1.34 % were obtained under an illumination of 100 mw/cm2.展开更多
{001}facets dominated single crystalline anatase TiO_(2) nanosheet array(TNSA)was synthe-sized through an optimized organic solvothermal route on uorine-doped tin oxide substrate.The field emission scanning electron m...{001}facets dominated single crystalline anatase TiO_(2) nanosheet array(TNSA)was synthe-sized through an optimized organic solvothermal route on uorine-doped tin oxide substrate.The field emission scanning electron microscopy images and X-ray diffraction patterns re-vealed that the{001}synthesized facets dominated TNSA exhibited much higher orientation than that synthesized by hydrothermal route.The TNSAs were loaded with Pt nanoparti-cles in uniformly size by using a photodecomposition method,which were further con rmed by high resolution transmission electron microscopy(HRTEM).The HRTEM images also revealed that Pt nanoparticles preferred to deposit on{001}facets.With loading of Pt nanoparticles,the optical absorbance was significantly enhanced,while the photolumines-cence(PL)was inhibited.The photocatalytic activity of TNSA was signi cantly improved by Pt loading and reached the maximum with optimal amount of Pt loading.The optimal amount of Pt on{001}facets is far less than that on TiO_(2) nanoparticles,which may be attributed to the specific atom structure of reactive{001}facets.展开更多
The rutile TiO2 nanorod arrays with 240 nm in length, 30 nm in diameter, and 420 btm 2 in areal density were prepared by the hydrothermal method to replace the typical 200-300 nm thick mesoporous TiO2 thin films in pe...The rutile TiO2 nanorod arrays with 240 nm in length, 30 nm in diameter, and 420 btm 2 in areal density were prepared by the hydrothermal method to replace the typical 200-300 nm thick mesoporous TiO2 thin films in perovskite solar cells. The CH3NH3PbI3 xBrx capping layers with different thicknesses were obtained on the TiO2 nanorod arrays using different concentration PbI2.DMSO complex precursor solutions in DMF and the photovoltaic performances of the corresponding solar cells were compared. The perovskite solar cells based on 240 nm long TiO2 nanorod arrays and 420 nm thick CH3NH3PbI3 xBrx capping layers showed the best photoelectric conversion efficiency （PCE） of 15.56% and the average PCE of 14.93 ± 0.63% at the relative humidity of 50%-54% under the illumination of simulated AM 1.5 sunlight （100 mW.cm-2）.展开更多
Recently,a novel 2-electron oxygen reduction reaction(ORR)based electro-oxidation(EO)system was developed,which utilizes a H_(2)O_(2)generation cathode instead of H_(2)evolution cathode.A Ti-based Ni-Sb co-doped SnO_(...Recently,a novel 2-electron oxygen reduction reaction(ORR)based electro-oxidation(EO)system was developed,which utilizes a H_(2)O_(2)generation cathode instead of H_(2)evolution cathode.A Ti-based Ni-Sb co-doped SnO_(2)(Ti/NATO)anode was selected for efficient degradation of refractory organics and O_(3)production.The synergistic reaction of O3/H_(2)O_(2)further accelerated the generation of hydroxyl radicals(·OH)in the ORR-EO system.However,the catalytic activity and long-term effectiveness of the Ti/NATO anode limited the large-scale application of the ORR-EO process.In this study,a blue TiO_(2)nanotube array(blue-TiO_(2)-NTA)inter-layer was introduced into the fabrication process between the Ti substrate and NATO catalyst layer.Compared to the Ti/NATO anode,the Ti/blue-TiO_(2)-NTA/NATO anode achieved higher efficiency of organic removal and O_(3)generation.Additionally,the accelerated lifetime of the Ti/blue-TiO_(2)-NTA/NATO anode was increased by 7 times compared to the Ti/NATO anode.When combined with CNTs-C/PTFE air cathode in ORR-EO system,all anodic oxidation and O_(3)/H_(2)O_(2)processes achieved higher•OH production.Over 92%of TOC in leachate bio-effluent was effectively eliminated with a relatively low energy cost of 45 kWh/t.展开更多
基金financially supported by the National Natural Science Foundation of China (22005097)the State Key Laboratory of Physical Chemistry of Solid Surfaces,Xiamen University,Xiamen 361005,P.R.China (201815)。
文摘Efficiently and thoroughly degrading organic dyes in wastewater is of great importance and challenge.Herein,vertically oriented mesoporous a-Fe_(2)O_(3)nanorods array(a-Fe_(2)O_(3)-NA)is directly grown on fluorine-doped tin oxide(FTO)glass and employed as the photoanode for photoelectrocatalytic degradation of methylene blue simulated dye wastewater.The Ovsites on the a-Fe_(2)O_(3)-NA surface are the active sites for methylene blue(MB)adsorption.Electrons transfer from the adsorbed MB to Fe-O is detected.Compared with electrocatalytic and photocatalytic degradation processes,the photoelectrocatalytic(PEC)process exhibited the best degrading performance and the largest kinetic constant.Hydroxyl,superoxide free radicals,and photo-generated holes play a jointly leading role in the PEC degradation.A possible degrading pathway is suggested by liquid chromatography-mass spectroscopy analysis.This work demonstrates that photoelectrocatalysis by a-Fe_(2)O_(3)-NA has a remarkable superiority over photocatalysis and electrocatalysis in MB degradation.The in-depth investigation of photoelectrocatalytic degradation mechanism in this study is meaningful for organic wastewater treatment.
文摘Low optical absorption and photocorrosion are two crucial issues limiting the practical applications of zinc oxide(ZnO)-based photocatalysts.In this paper,we report the fabrication of graphitic-carbon-mediated ZnO nanorod arrays(NRAs)with enhanced photocatalytic activity and photostability for CO2 reduction under visible light irradiation.ZnO NRA/C-x(x=005,01,02,and 03)nanohybrids are prepared by calcining pre-synthesized ZnO NRAs with different amounts of glucose(0.05,0.1,0.2,and 0.3 g)as a carbon source via a hydrothermal method.X-ray photoelectron spectroscopy reveals that the obtained ZnO NRA/C-x nanohybrids are imparted with the effects of both carbon doping and carbon coating,as evidenced by the detected C-O-Zn bond and the C-C,C-O and C=O bonds,respectively.While the basic structure of ZnO remains unchanged,the UV-Vis absorption spectra show increased absorbance owing to the carbon doping effect in the ZnO NRA/C-x nanohybrids.The photoluminescence(PL)intensities of ZnO NRA/C-x nanohybrids are lower than that of bare ZnO NRA,indicating that the graphitic carbon layer coated on the surface of the ZnO NRA significantly enhances the charge carrier separation and transport,which in turn enhances the photoelectrochemical property and photocatalytic activity of the ZnO NRA/C-x nanohybrids for CO2 reduction.More importantly,a long-term reaction of photocatalytic CO2 reduction demonstrates that the photostability of ZnO NRA/C-x nanohybrids is significantly increased in comparison with the bare ZnO NRA.
基金supported by the National Key Research and Development Program of China(2019YFA0705400 and 2019YFD0901100)the National Natural Science Foundation of China(21991151,21925404,and 21775127)+1 种基金the“111”Project(B17027)Guangdong Basic and Applied Basic Research Foundation(2020A1515010510)。
文摘All-solid-state Z-scheme photocatalysts for overall water splitting to evolve H_(2) is a promising strategy for efficient conversion of solar energy.However,most of these strategies require redox mediators.Herein,a direct Z-scheme photoelectrocatalytic electrode based on a WO_(3-x)nanowire-bridged TiO_(2)nanorod array heterojunction is constructed for overall water splitting,producing H_(2).The as-prepared WO_(3-x)/TiO_(2)nanorod array heterojunction shows photoelectrochemical(PEC)overall water splitting activity evolving both H_(2) and O_(2)under UV-vis light irradiation.An optimum PEC activity was achieved over a 1.67-WO_(3-x)/TiO_(2)photoelectrode yielding maximum H_(2) and O_(2)evolution rates roughly 11 times higher than that of pure TiO_(2)nanorods without any sacrificial agent or redox mediator.The role of oxygen vacancy in WO_(3-x)in affecting the H_(2) production rate was also comprehensively studied.The superior PEC activity of the WO_(3-x)/TiO_(2)electrode for overall water splitting can be ascribed to an efficient Z-scheme charge transfer pathway between the WO_(3-x)nanowires and TiO_(2)nanorods,the presence of oxygen vacancies in WO_(3-x),and a bias potential applied on the photoelectrode,resulting in effective spatial charge separation.This study provides a novel strategy for developing highly efficient PECs for overall water splitting.
基金Project supported by the Fundamental Research Funds for the Central Universities,China(Grant No.2013XK07)
文摘TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells. Vertically aligned Tit2 nanorod arrays （NRs） are grown on the fluorine-doped tin oxide （FTO） substrates by a multicycle hydrothermal synthesis process. The samples are characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, high-resolution transmission electron microscopy （HRTEM）, and selected-area electron diffraction （SAED）. It is found that dye-sensitized solar cells （DSSCs） assembled by the as-prepared Tit2 single-crystal NRs exhibit different trends under the condition of different nucleation and growth concentrations. Optimum cell performance is obtained with high nucleation concentration and low growth cycle concentration. The efficiency enhancement is mainly attributed to the improved specific surface area of the nanorod.
基金National Natural Science Foundation of China(No.11174071)the International Cooperation Project of Wuhan City and Hubei Province(Nos.201070934339 and 2010BFA010)
文摘CdSe/CdS semiconductor quantum dots co-sensitized TiO2 nanorod array was fabricated on the transparent conductive fluorine-doped tin oxide （FTO） substrate using the hydrothermal and successive ionic layer adsorption and reaction （SILAR） process. The structural and morphological properties of the samples were characterized by X-ray diffraction （XRD）, field-emission scanning electron microscopy （FESEM）, and transmission electron microscopy （TEM）. The results indicate that CdSe/CdS QDs are uniformly coated on the surface of the TiO2 nanorods. The shift of light absorption edge was monitored by taking UV-visible absorption spectra. Compared with the absorption spectra of the TiO2 nanorod array, deposition of CdSe/CdS QDs shifts the absorption edge to the higher wavelength. The enhanced light absorption in the visible-light region of CdSe/CdS/TiO2 nanorod array indicates that CdSe/CdS layers can act as co-sensitizers in quantum dots sensitized solar cells （QDSSCs）. By optimizing the CdSe layer deposition cycles, a photocurrent of 5.78 mA/cm2, an open circuit photovoltage of 0.469 V and a conversion efficiency of 1.34 % were obtained under an illumination of 100 mw/cm2.
基金This work is supported by the National Basic Research Program of China(No.2012CB9222000).
文摘{001}facets dominated single crystalline anatase TiO_(2) nanosheet array(TNSA)was synthe-sized through an optimized organic solvothermal route on uorine-doped tin oxide substrate.The field emission scanning electron microscopy images and X-ray diffraction patterns re-vealed that the{001}synthesized facets dominated TNSA exhibited much higher orientation than that synthesized by hydrothermal route.The TNSAs were loaded with Pt nanoparti-cles in uniformly size by using a photodecomposition method,which were further con rmed by high resolution transmission electron microscopy(HRTEM).The HRTEM images also revealed that Pt nanoparticles preferred to deposit on{001}facets.With loading of Pt nanoparticles,the optical absorbance was significantly enhanced,while the photolumines-cence(PL)was inhibited.The photocatalytic activity of TNSA was signi cantly improved by Pt loading and reached the maximum with optimal amount of Pt loading.The optimal amount of Pt on{001}facets is far less than that on TiO_(2) nanoparticles,which may be attributed to the specific atom structure of reactive{001}facets.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51472071 and 51272061)Talent Project of Hefei University of Technology,China(Grant Nos.75010-037004 and 75010-037003)
文摘The rutile TiO2 nanorod arrays with 240 nm in length, 30 nm in diameter, and 420 btm 2 in areal density were prepared by the hydrothermal method to replace the typical 200-300 nm thick mesoporous TiO2 thin films in perovskite solar cells. The CH3NH3PbI3 xBrx capping layers with different thicknesses were obtained on the TiO2 nanorod arrays using different concentration PbI2.DMSO complex precursor solutions in DMF and the photovoltaic performances of the corresponding solar cells were compared. The perovskite solar cells based on 240 nm long TiO2 nanorod arrays and 420 nm thick CH3NH3PbI3 xBrx capping layers showed the best photoelectric conversion efficiency （PCE） of 15.56% and the average PCE of 14.93 ± 0.63% at the relative humidity of 50%-54% under the illumination of simulated AM 1.5 sunlight （100 mW.cm-2）.
基金We are thankful to the National Natural Science Foundation of China(22174110 and 22127803)the Industrial Support Plan of Gansu Provincial Department of Education(2021cyzc-01)the Special Fund Project for Guiding Local Scientific and Technological Development by the Central Government(2020-2060503-17).
基金supported by grants from the National Natural Science Foundation of China(No.52070008).
文摘Recently,a novel 2-electron oxygen reduction reaction(ORR)based electro-oxidation(EO)system was developed,which utilizes a H_(2)O_(2)generation cathode instead of H_(2)evolution cathode.A Ti-based Ni-Sb co-doped SnO_(2)(Ti/NATO)anode was selected for efficient degradation of refractory organics and O_(3)production.The synergistic reaction of O3/H_(2)O_(2)further accelerated the generation of hydroxyl radicals(·OH)in the ORR-EO system.However,the catalytic activity and long-term effectiveness of the Ti/NATO anode limited the large-scale application of the ORR-EO process.In this study,a blue TiO_(2)nanotube array(blue-TiO_(2)-NTA)inter-layer was introduced into the fabrication process between the Ti substrate and NATO catalyst layer.Compared to the Ti/NATO anode,the Ti/blue-TiO_(2)-NTA/NATO anode achieved higher efficiency of organic removal and O_(3)generation.Additionally,the accelerated lifetime of the Ti/blue-TiO_(2)-NTA/NATO anode was increased by 7 times compared to the Ti/NATO anode.When combined with CNTs-C/PTFE air cathode in ORR-EO system,all anodic oxidation and O_(3)/H_(2)O_(2)processes achieved higher•OH production.Over 92%of TOC in leachate bio-effluent was effectively eliminated with a relatively low energy cost of 45 kWh/t.
