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
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
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
Fluorine-doped tin oxide(FTO)/TiO_(2) seed layer/TiO_(2) nanorods were prepared by ion-beam deposition and hydrothermal methods.Under UV light,the photocurrent density of these nanorods was found to reach 1.39 mA/cm^(...Fluorine-doped tin oxide(FTO)/TiO_(2) seed layer/TiO_(2) nanorods were prepared by ion-beam deposition and hydrothermal methods.Under UV light,the photocurrent density of these nanorods was found to reach 1.39 mA/cm^(2),which was higher than that without the seed layer and nanorod structures.Furthermore,the FTO/TiO_(2) seed layer/TiO_(2) nanorods can also absorb visible light,overcoming a notable problem with standard TiO_(2).The photocurrent density of the FTO/TiO_(2) seed layer/TiO_(2) nanorods was found to reach 0.21 mA/cm^(2) under visible light.This high-performance results from the deposition of the TiO_(2) seed layer,which reduces the band gap of TiO_(2).The FTO/TiO_(2) seed layer/TiO_(2) nanorods also exhibited high photodegradation ability for the organic pollutant methylene blue(MB).Within 120 min,77.3%of the MB was found to have been degraded,and the degradation rates remained almost unchanged after four cycles with the same catalyst sample.Additionally,compared with powdered photocatalysts,the FTO/TiO_(2) seed layer/TiO_(2) nanorod sample is easy to recover,requiring only rinsing with water and natural drying after the reaction.展开更多
The solar-to-hydrogen conversion using the photoelectrochemical(PEC)method is a practical approach to producing clean energy.However,it relies on the availability of photocatalyst materials.In this work,a novel photoc...The solar-to-hydrogen conversion using the photoelectrochemical(PEC)method is a practical approach to producing clean energy.However,it relies on the availability of photocatalyst materials.In this work,a novel photocatalyst comprising molybdenum telluride quantum dots(MoTe_(2) QDs)-modified titanium dioxide nanorods(TiO_(2) NRs)was prepared for the enhancement of the PEC water splitting performance after combination with a Al_(2)O_(3) layer using the atomic layer deposition(ALD)technique.MoTe_(2) QDs were initially prepared,and then they were loaded onto TiO_(2) NRs using a warm water bath-based heating method.After a layer of Al_(2)O_(3) was deposited onto resulted TiO_(2) NRs/MoTe_(2) QDs,the composite TiO_(2) NRs/MoTe_(2) QDs/Al_(2)O_(3) was finally obtained.Under simulated sunlight(100 mW·cm^(-2)),such a composite exhibited a maximum photocurrent density of 2.25 mA·cm^(-2) at 1.23 V(versus RHE)and an incident photon-to-electron conversion efficiency of 69.88%at 380 nm,which are 4.33 and 6.66 times those of pure TiO_(2) NRs,respectively.Therefore,the composite photocatalyst fabricated in this work may have promising application in the field of PEC water splitting,solarcells andotherphotocatalyticdevices.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.
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This work was supported by Tianjin Natural Science Foundation(Grant No.19JCQNJC06200)Major Projects of Science and Technology in Tianjin(Grant No.18ZXJMTG00020).
文摘Fluorine-doped tin oxide(FTO)/TiO_(2) seed layer/TiO_(2) nanorods were prepared by ion-beam deposition and hydrothermal methods.Under UV light,the photocurrent density of these nanorods was found to reach 1.39 mA/cm^(2),which was higher than that without the seed layer and nanorod structures.Furthermore,the FTO/TiO_(2) seed layer/TiO_(2) nanorods can also absorb visible light,overcoming a notable problem with standard TiO_(2).The photocurrent density of the FTO/TiO_(2) seed layer/TiO_(2) nanorods was found to reach 0.21 mA/cm^(2) under visible light.This high-performance results from the deposition of the TiO_(2) seed layer,which reduces the band gap of TiO_(2).The FTO/TiO_(2) seed layer/TiO_(2) nanorods also exhibited high photodegradation ability for the organic pollutant methylene blue(MB).Within 120 min,77.3%of the MB was found to have been degraded,and the degradation rates remained almost unchanged after four cycles with the same catalyst sample.Additionally,compared with powdered photocatalysts,the FTO/TiO_(2) seed layer/TiO_(2) nanorod sample is easy to recover,requiring only rinsing with water and natural drying after the reaction.
基金The authors thank the National Natural Science Foundation of China(Grant Nos.52205230 and U21A2046)the Key Research and Development Program in Shandong Province(No.SYS202203)+4 种基金the Program for Taishan Scholars of Shandong Province(No.TS20190965)the Key Research Program of the Chinese Academy of Sciences(Grant No.ZDBS-ZRKJZ-TLCO10)the Western Light Project of CAS(xbzg-zdsys-202118)the Major Science and Technology Projects in Gansu Province(No.22ZD6GA002)the Major Program of the Lanzhou Institute of Chemical Physics,CAS(No.ZYFZFX-5)for providing financial support.
文摘The solar-to-hydrogen conversion using the photoelectrochemical(PEC)method is a practical approach to producing clean energy.However,it relies on the availability of photocatalyst materials.In this work,a novel photocatalyst comprising molybdenum telluride quantum dots(MoTe_(2) QDs)-modified titanium dioxide nanorods(TiO_(2) NRs)was prepared for the enhancement of the PEC water splitting performance after combination with a Al_(2)O_(3) layer using the atomic layer deposition(ALD)technique.MoTe_(2) QDs were initially prepared,and then they were loaded onto TiO_(2) NRs using a warm water bath-based heating method.After a layer of Al_(2)O_(3) was deposited onto resulted TiO_(2) NRs/MoTe_(2) QDs,the composite TiO_(2) NRs/MoTe_(2) QDs/Al_(2)O_(3) was finally obtained.Under simulated sunlight(100 mW·cm^(-2)),such a composite exhibited a maximum photocurrent density of 2.25 mA·cm^(-2) at 1.23 V(versus RHE)and an incident photon-to-electron conversion efficiency of 69.88%at 380 nm,which are 4.33 and 6.66 times those of pure TiO_(2) NRs,respectively.Therefore,the composite photocatalyst fabricated in this work may have promising application in the field of PEC water splitting,solarcells andotherphotocatalyticdevices.
