Visible light-induced two-step overall water-splitting was achieved by combining two types of photocatalysts, which were prepared by introducing foreign elements into rutile titanium dioxide (TiO2) and strontium titan...Visible light-induced two-step overall water-splitting was achieved by combining two types of photocatalysts, which were prepared by introducing foreign elements into rutile titanium dioxide (TiO2) and strontium titanate (SrTiO3) with a controlled electronic band structure. Rutile TiO2 and SrTiO3 were doped with chromium and tantalum (Cr,Ta-TiO2) and with rhodium (Rh-SrTiO3), respectively, to introduce visible-light sensitivity. Under irradiation with only visible light from a 420-nm LED lamp, the simultaneous liberation of hydrogen and oxygen with a molar ratio of ~2:1 was achieved with these two types of photocatalysts in the presence of iodate ion/iodide ion as a redox mediator.展开更多
Layered Aurivillius compound Bi_(5)Ti_(3)CrO_(15) has been synthesized by a hydrothermal method for the application as a photocatalyst to liberate hydrogen from water. Bi_(5)Ti_(3)CrO_(15) owns a narrow band gap (Eg ~...Layered Aurivillius compound Bi_(5)Ti_(3)CrO_(15) has been synthesized by a hydrothermal method for the application as a photocatalyst to liberate hydrogen from water. Bi_(5)Ti_(3)CrO_(15) owns a narrow band gap (Eg ~2.46 eV) and shows stable photocatalytic activity under both full range (λ ≥250 nm) and visible light illumination (λ ≥420 nm). A short hydrothermal reaction time is critical to achieve high photocatalytic activity as defects such as Cr^(6+) and Bi^(5+) can be avoided. An AQE as high as 3.66% at 420 nm ± 20 nm has been recorded, warranting promising application in the field of solar energy conversions. DFT calculation reveals the important role of Cr^(3+) cations for visible light sensitivity of Bi_(5)Ti_(3)CrO_(15).展开更多
Photocatalytic (PC) / Photoelectrochemical (PEC) water splitting under solar light irradiation is considered as a prospective technique to support the sustainable and renewable H_(2) economy and to reach the ultime go...Photocatalytic (PC) / Photoelectrochemical (PEC) water splitting under solar light irradiation is considered as a prospective technique to support the sustainable and renewable H_(2) economy and to reach the ultime goal of carbon neutral. TiO_(2) based photocatalysts with high chemical stability and excellent photocatalytic properties have great potential for solar-to-H_(2) conversion. To conquer the challenges of the large band-gap and rapid recombination of photo generated electron-holepairs in TiO_(2), non-metal doping turns out to be economic, facile, and effective on boosting the visible light activity. The localized defect states such as oxygen vacancy and Ti^(3+) generated by non-metal doping are located in the band-gap of TiO_(2), which result in the reduction of band-gap, thus a red-shift of the absorption edge. The hetero doping atoms such as B^(3+), I^(7+), S^(4+)/S^(6+), P^(5+) can also act as electron donors or trap sites which facilitate the charge carrier separation and suppress the recombination of electron-hole pairs. In this comprehensive review, we present the most recent advances on non-metal doped TiO_(2) photocatalysts in terms of fundamental aspects, origin of visible light activity and the PC / PEC behaviours for water splitting. In particular, the characteristics of different non-metal elements (N, C, B, S, P, Halogens) as dopants are discussed in details focusing on the synthesis approaches, characterization as well as the efficiency of PC and PEC water splitting. The present review aims at guiding the readers who want quick access to helpful information about how to efficiently improve the performance of photocatalysts by simple doping strategies and could stimulate new intuitive into the new doping strategies.展开更多
In this paper,a visible light-responsive Sn^(2+)and N co-doped TiO_(2)photocatalyst was prepared by facile one-pot hydrothermal method.All as-prepared samples were characterized in detail by a series of characterizati...In this paper,a visible light-responsive Sn^(2+)and N co-doped TiO_(2)photocatalyst was prepared by facile one-pot hydrothermal method.All as-prepared samples were characterized in detail by a series of characterization approaches.The results showed that the Sn^(2+)and N elements were co-doped into TiO_(2),while the catalyst still maintains anatase crystal structure and gets irregular little nanocluster in diameter of 9–10 nm with higher specific surface area.The absorption edge of Sn^(2+)and N co-doped TiO_(2)extends to the visible light region.Compared with Sn^(2+)-doped TiO_(2)and N-TiO_(2),the absorption edges have obvious red-shift of about 50 and 70 nm,respectively.The synergistic effect of O 2p-N 2p and O 2p-Sn 5s hybridization to form impurity levels is the main reason for the red-shift.The hydrogen production performance of the Sn^(2+)and N co-doping TiO_(2)(n(N)/n(Ti)=1)catalyst reached the maximum value of 0.37 mmol·h^(-1)·g^(-1)under visible light,which is higher than that of N-doped TiO_(2)and SnTiO_(2)-doped TiO_(2)singly.This result is due to the wider visible light region-responsive ability of Sn^(2+)and N codoped into TiO_(2).Furthermore,mild hydrothermal methods will not make the Sn^(2+)oxidized to Sn^(4+),which make the catalysts still maintain high photocatalytic performance.This work provides a simple and mild method for the preparation of dual-element co-doped TiO_(2)with high crystallinity,excellent performance and broad application prospects.展开更多
The hybridization between the outmost s orbitals of metal(Bi^(3+),Sn^(2+),Pb^(2+),Ag^(+))and O 2 p orbitals has been widely employed to develop innovative semiconductors with upshift valence band as well as extended v...The hybridization between the outmost s orbitals of metal(Bi^(3+),Sn^(2+),Pb^(2+),Ag^(+))and O 2 p orbitals has been widely employed to develop innovative semiconductors with upshift valence band as well as extended visible light response,but it is still challenging to obtain photocatalyst with absorption edge of above 550 nm.Here we report a novel Sn^(2+)-based oxyfluoride Sn_(2)TiNbO_6 F(STNOF)photocatalyst with a pyrochlore structure to exhibit an extended absorption edge to 650 nm and dual functionalities of both water reduction and oxidation.Density functional theory calculations suggest that the unprecedented broad-spectrum response of STNOF is mainly ascribed to the strengthened hybridization between O 2 p and Sn 5 s orbitals remarkably upshifting the valence band,which is caused by the distortion and compressive strain in the Sn06 F2 dodecahedron with second-order Jahn-Teller effect due to partial fluorine substitution.The structural distortion and compressive strain are experimentally confirmed by the Fourier-transformed extended X-ray absorption fine spectra.As probe tests of the photocatalytic functionalities,water reduction and oxidation half reactions were examined to see obvious H_(2)and O_(2)evolution under visible light irradiation.This work may provide an alternative strategy of developing extended visible light responsive semiconductors for promising solar energy conversion.展开更多
Recently,the combination of plasmonic noble metallic nanostructures with semiconductors for plasmonenhanced visible light-driven water splitting(WS)has attracted considerable attention.This review first presents three...Recently,the combination of plasmonic noble metallic nanostructures with semiconductors for plasmonenhanced visible light-driven water splitting(WS)has attracted considerable attention.This review first presents three prime enhancement mechanisms for plasmon-enhanced photocatalytic WS,and then some state-of-the-art representative studies are introduced according to different enhancement mechanisms.Furthermore,the design parameters of plasmonic-metal/semiconductor photocatalysts are discussed in detail,focusing on the effect of shape,size and geometric position of metallic nanostructures on the photocatalytic activity of visible light-driven WS.Finally,the challenges and perspectives for plasmon-enhanced solar WS are proposed.展开更多
Visible light driven tin oxide based photoelectrodes were obtained using SnCl2·2H2O EtOH solution on FTO by dipping and with further heat treatment in air.Photoelectrochemical measurement with three electrodes co...Visible light driven tin oxide based photoelectrodes were obtained using SnCl2·2H2O EtOH solution on FTO by dipping and with further heat treatment in air.Photoelectrochemical measurement with three electrodes configuration under visible light irradiation(λ>420 nm) revealed that this as-prepared photoelectrode showed typical n-type photocurrent effect and the onset potential is negative than that of H+/H2.XRD,UV-Vis spectrum and control experimental results revealed that the visible light driven mechanism for the tin oxide based photoanode maybe ascribed to Sn4+/Sn2+ transformation and the surface oxygen deficiency.展开更多
The mesoporous photocatalyst InVO4 was synthesized by the template-directing self-assembling method.The synthesized InVO4 was characterized by means of X-ray diffraction,transmission electron microscopy,N2 adsorption,...The mesoporous photocatalyst InVO4 was synthesized by the template-directing self-assembling method.The synthesized InVO4 was characterized by means of X-ray diffraction,transmission electron microscopy,N2 adsorption,and ultraviolet-visible spectroscopy.The results showed that the crystal structure of InVO4 could be controlled by changing the calcination temperature.Compared with the anatase TiO2 and conventional InVO4,the mesoporous InVO4 was more responsive toward visible light.The evolution rate of H2 from water over the mesoporous InVO4 achieved（1?836） μmol/（g·h） under UV light irradiation, which was much higher than the anatase TiO2 and conventional InVO4.展开更多
基金Key Project of Chinese Ministry of Education （No. 105105）, Program for New Century Excellent Talents in University of Chinese Ministry of Education （No. NCET-04-0643）, and the Taishan Mountain Scholar Construction Engineering Special Fund of Shandong Province, China.
文摘Visible light-induced two-step overall water-splitting was achieved by combining two types of photocatalysts, which were prepared by introducing foreign elements into rutile titanium dioxide (TiO2) and strontium titanate (SrTiO3) with a controlled electronic band structure. Rutile TiO2 and SrTiO3 were doped with chromium and tantalum (Cr,Ta-TiO2) and with rhodium (Rh-SrTiO3), respectively, to introduce visible-light sensitivity. Under irradiation with only visible light from a 420-nm LED lamp, the simultaneous liberation of hydrogen and oxygen with a molar ratio of ~2:1 was achieved with these two types of photocatalysts in the presence of iodate ion/iodide ion as a redox mediator.
基金This work was supported by the National Natural Science Foundation of China(No.51972233)the Natural Science Foundation of Shanghai(No.19ZR1459200)+1 种基金the Shanghai Science and Technology Commission(No.14DZ2261100)the Fundamental Research Funds for the Central Universities.We also thank Prof.Hongying Zhao for EPR analysis.
文摘Layered Aurivillius compound Bi_(5)Ti_(3)CrO_(15) has been synthesized by a hydrothermal method for the application as a photocatalyst to liberate hydrogen from water. Bi_(5)Ti_(3)CrO_(15) owns a narrow band gap (Eg ~2.46 eV) and shows stable photocatalytic activity under both full range (λ ≥250 nm) and visible light illumination (λ ≥420 nm). A short hydrothermal reaction time is critical to achieve high photocatalytic activity as defects such as Cr^(6+) and Bi^(5+) can be avoided. An AQE as high as 3.66% at 420 nm ± 20 nm has been recorded, warranting promising application in the field of solar energy conversions. DFT calculation reveals the important role of Cr^(3+) cations for visible light sensitivity of Bi_(5)Ti_(3)CrO_(15).
基金supported by the National Natural Science Foundation of China(U1663225,21805280 and 21805220)the Youth Innovation Foundation of Xiamen City:3502Z20206085+4 种基金Program for Changjiang Scholars and Innovative Research Team in University(IRT_15R52)The Opening Project of PCOSS,Xiamen University,201907the program of introducing Talents of discipline to Universities-111 Project(Grant No.B20002)the project“Depollut Air”of Interreg V France-Wallonie-Vlaanderenthe financial support from the China Scholarship Council(CSC)。
文摘Photocatalytic (PC) / Photoelectrochemical (PEC) water splitting under solar light irradiation is considered as a prospective technique to support the sustainable and renewable H_(2) economy and to reach the ultime goal of carbon neutral. TiO_(2) based photocatalysts with high chemical stability and excellent photocatalytic properties have great potential for solar-to-H_(2) conversion. To conquer the challenges of the large band-gap and rapid recombination of photo generated electron-holepairs in TiO_(2), non-metal doping turns out to be economic, facile, and effective on boosting the visible light activity. The localized defect states such as oxygen vacancy and Ti^(3+) generated by non-metal doping are located in the band-gap of TiO_(2), which result in the reduction of band-gap, thus a red-shift of the absorption edge. The hetero doping atoms such as B^(3+), I^(7+), S^(4+)/S^(6+), P^(5+) can also act as electron donors or trap sites which facilitate the charge carrier separation and suppress the recombination of electron-hole pairs. In this comprehensive review, we present the most recent advances on non-metal doped TiO_(2) photocatalysts in terms of fundamental aspects, origin of visible light activity and the PC / PEC behaviours for water splitting. In particular, the characteristics of different non-metal elements (N, C, B, S, P, Halogens) as dopants are discussed in details focusing on the synthesis approaches, characterization as well as the efficiency of PC and PEC water splitting. The present review aims at guiding the readers who want quick access to helpful information about how to efficiently improve the performance of photocatalysts by simple doping strategies and could stimulate new intuitive into the new doping strategies.
基金This study was financially supported by the Natural Science Foundation of China(No.21663009)the National Key R&D Projects of China(No.2018YFC1801706-01)the Science and Technology Supporting Project of Guizhou Province(Nos.[2019]2835 and[2021]480).
文摘In this paper,a visible light-responsive Sn^(2+)and N co-doped TiO_(2)photocatalyst was prepared by facile one-pot hydrothermal method.All as-prepared samples were characterized in detail by a series of characterization approaches.The results showed that the Sn^(2+)and N elements were co-doped into TiO_(2),while the catalyst still maintains anatase crystal structure and gets irregular little nanocluster in diameter of 9–10 nm with higher specific surface area.The absorption edge of Sn^(2+)and N co-doped TiO_(2)extends to the visible light region.Compared with Sn^(2+)-doped TiO_(2)and N-TiO_(2),the absorption edges have obvious red-shift of about 50 and 70 nm,respectively.The synergistic effect of O 2p-N 2p and O 2p-Sn 5s hybridization to form impurity levels is the main reason for the red-shift.The hydrogen production performance of the Sn^(2+)and N co-doping TiO_(2)(n(N)/n(Ti)=1)catalyst reached the maximum value of 0.37 mmol·h^(-1)·g^(-1)under visible light,which is higher than that of N-doped TiO_(2)and SnTiO_(2)-doped TiO_(2)singly.This result is due to the wider visible light region-responsive ability of Sn^(2+)and N codoped into TiO_(2).Furthermore,mild hydrothermal methods will not make the Sn^(2+)oxidized to Sn^(4+),which make the catalysts still maintain high photocatalytic performance.This work provides a simple and mild method for the preparation of dual-element co-doped TiO_(2)with high crystallinity,excellent performance and broad application prospects.
基金financially supported by the National Natural Science Foundation of China(NSFC)(22088102)supported by the National Natural Science Foundation of China(21633009,21633010,21925206)+4 种基金the Cooperation Fund of Dalian National Laboratory for Clean Energy(DNL201913)International Partnership Program of Chinese Academy of Sciences(121421KYSB20190025)the DICP foundation of innovative research(DICPI201927)Strategic Priority Research Pro-gram of Chinese Academy of Sciences(XDB17000000)support from Liaoning Revitalization Talents Program(XLYC1807241)。
文摘The hybridization between the outmost s orbitals of metal(Bi^(3+),Sn^(2+),Pb^(2+),Ag^(+))and O 2 p orbitals has been widely employed to develop innovative semiconductors with upshift valence band as well as extended visible light response,but it is still challenging to obtain photocatalyst with absorption edge of above 550 nm.Here we report a novel Sn^(2+)-based oxyfluoride Sn_(2)TiNbO_6 F(STNOF)photocatalyst with a pyrochlore structure to exhibit an extended absorption edge to 650 nm and dual functionalities of both water reduction and oxidation.Density functional theory calculations suggest that the unprecedented broad-spectrum response of STNOF is mainly ascribed to the strengthened hybridization between O 2 p and Sn 5 s orbitals remarkably upshifting the valence band,which is caused by the distortion and compressive strain in the Sn06 F2 dodecahedron with second-order Jahn-Teller effect due to partial fluorine substitution.The structural distortion and compressive strain are experimentally confirmed by the Fourier-transformed extended X-ray absorption fine spectra.As probe tests of the photocatalytic functionalities,water reduction and oxidation half reactions were examined to see obvious H_(2)and O_(2)evolution under visible light irradiation.This work may provide an alternative strategy of developing extended visible light responsive semiconductors for promising solar energy conversion.
基金This project is sponsored by NSFC （Nos. 21325415, 21174019, 21301018, 51161120361）, National Basic Research Program of China （2011CB013000）, Basic Research Foundation of Beijing Institute of Technology （20121942008）, Fok Ying Tong Education Foundation （No. 131043）, the 111 Project B07012, Beijing Natural Science Foundation （2152028） and the Beijing Key Laboratory for Chemical Power Source and Green Catalysis under the contract no. 2013CX02031.
基金Financial support from the Natural Sciences and Engineering Research Council of Canada(RGPIN-2015-06756)Canada Research Chairs Program(950-212323)+3 种基金le Fonds de recherche du Quebec-Nature et technologies(FRQNT)is greatly appreciated.In addition,Q.Zhang acknowledges the support under State Scholarship Fund from the China Scholarship Council(CSC,NO.201506220152)D.Thrithamarassery Gangadharan acknowledges the support from FRQNT Merit scholarship program for foreign students(199772)Dr.Z.Xu acknowledges the National Natural Science Foundation of China(NSFC 51402198)Natural Science Foundation of Liaoning Province(201602592)for financial support.
文摘Recently,the combination of plasmonic noble metallic nanostructures with semiconductors for plasmonenhanced visible light-driven water splitting(WS)has attracted considerable attention.This review first presents three prime enhancement mechanisms for plasmon-enhanced photocatalytic WS,and then some state-of-the-art representative studies are introduced according to different enhancement mechanisms.Furthermore,the design parameters of plasmonic-metal/semiconductor photocatalysts are discussed in detail,focusing on the effect of shape,size and geometric position of metallic nanostructures on the photocatalytic activity of visible light-driven WS.Finally,the challenges and perspectives for plasmon-enhanced solar WS are proposed.
基金supported by the National Natural Science Foundation of China (21103028)the Key Program of Society Development of Guizhou Province (SZ (2008)3008)+1 种基金the Key Program of Science and Technology of Guiyang City ((2008)014)the Cultivating Project of Guizhou Province (024)
文摘Visible light driven tin oxide based photoelectrodes were obtained using SnCl2·2H2O EtOH solution on FTO by dipping and with further heat treatment in air.Photoelectrochemical measurement with three electrodes configuration under visible light irradiation(λ>420 nm) revealed that this as-prepared photoelectrode showed typical n-type photocurrent effect and the onset potential is negative than that of H+/H2.XRD,UV-Vis spectrum and control experimental results revealed that the visible light driven mechanism for the tin oxide based photoanode maybe ascribed to Sn4+/Sn2+ transformation and the surface oxygen deficiency.
文摘The mesoporous photocatalyst InVO4 was synthesized by the template-directing self-assembling method.The synthesized InVO4 was characterized by means of X-ray diffraction,transmission electron microscopy,N2 adsorption,and ultraviolet-visible spectroscopy.The results showed that the crystal structure of InVO4 could be controlled by changing the calcination temperature.Compared with the anatase TiO2 and conventional InVO4,the mesoporous InVO4 was more responsive toward visible light.The evolution rate of H2 from water over the mesoporous InVO4 achieved（1?836） μmol/（g·h） under UV light irradiation, which was much higher than the anatase TiO2 and conventional InVO4.
基金supported by the National Natural Science Foundation of China (21173088)the Science and Technology Project of Guangdong Province (2014A030312007, 2015A050502012, 2016A010104013)+1 种基金the China Postdoctoral Science Foundation (2016M592493)the Open Research Fund of Hunan Key Laboratory of Applied Environmental Photocatalysis (CCSU-XT-06),Changsha University~~
文摘近几十年来,光电化学分解水制氢作为一种洁净的、能持续利用太阳能的技术受到极大关注.在众多光催化材料中,P型半导体氧化亚铜(Cu_2O)被认为是最有前途的可见光光电分解水材料之一.理论上,它的光能转换为氢能的效率可达到18.7%.然而,目前所报道的Cu_2O光转换效率远远低于此值;同时,纯Cu_2O在光照条件下的稳定性较差.研究表明,Cu_2O与其它半导体复合可以增强其光电转换效率和提高稳定性.如Cu_2O和能带匹配的石墨相氮化碳(g-C_3N_4)复合后,光催化性能和稳定性都有较大提高.但目前所报道的Cu_2O/g-C_3N_4复合物几乎都是粉末状催化剂,不便于回收和重复使用.本文首先采用电化学方法在FTO导电玻璃上沉积Cu_2O薄膜,采用溶胶凝胶法制备g-C_3N_4纳米颗粒材料,然后采用电化学法在Cu_2O薄膜表面沉积一层g-C_3N_4纳米颗粒,得到了Cu_2O/g-C_3N_4异质结膜.分别利用X射线粉末衍射(XRD)、高分辨透射电子显微镜(HRTEM)、扫描电子显微镜(SEM)、紫外可见光谱(UV-Vis)和光电化学分解水实验分析了Cu_2O/g-C_3N_4异质结的组成结构、表面形貌、光吸收性能及催化剂活性和稳定性.XRD和HRTEM表征显示,本文成功合成了Cu_2O/g-C_3N_4异质结材料,SEM图表明g-C_3N_4纳米颗粒在Cu_2O表面分布均匀,大小均一.可见光光电化学分解水结果显示,异质结薄膜的光电化学性能比纯的Cu_2O和g-C_3N_4薄膜材料有极大提高.当在Cu_2O表面沉积g-C_3N_4的时间为15 s时,得到样品Cu_2O/g-C_3N_4-15异质结膜,其在-0.4 V和可见光照射条件下,光电流密度达到了-1.38 mA/cm^2,分别是纯Cu_2O和g-C_3N_4薄膜材料的19.7和6.3倍.产氢速率也达到了0.48 mL h^(-1)cm^(-2),且产氢和产氧的速率之比约为2,说明此异质结材料在可见光作用下能全分解水.经过三次循环实验,光电化学分解水的效率仅降低10.8%,表明该材料具有良好的稳定性.根据UV-Vis表征和光电化学性能对比,Cu_2O/g-C_3N_4-15的光电性能最好,但其光吸收性能并不是最好,说明光电化学性能与光吸收不是成正比关系,主要是由于Cu_2O和g-C_3N_4两个半导体相互起到了协同作用.机理分析表明,Cu_2O/g-C_3N_4异质结薄膜在光照下,由于两者能带匹配,Cu_2O的光生电子从其导带转移到g-C_3N_4的导带上,g-C_3N_4价带上的空隙转移到Cu_2O的价带上,从而降低了光生电子和空隙的复合,提高了其光催化性能.由于g-C_3N_4的导带位置高于H_2O(或H^+)还原为H_2的电势,Cu_2O的价带位置低于H_2O(或OH-)还原为O_2的电势,所以在外加-0.4V偏压和可见光照射条件下,Cu_2O/g-C_3N_4能全分解水,光生载流子越多,光电化学分解水的速率越大.综上所述,在Cu_2O薄膜上沉积g-C_3N_4后得到的异质结薄膜具有高效的光能转换为氢能性能.
