UiO-66-NH2, as typical visible light responsive Zr-based metal-organic frameworks (MOFs), has attracted great interest in recent years. However, rapid combination of the photoinduced carriers limits its further applic...UiO-66-NH2, as typical visible light responsive Zr-based metal-organic frameworks (MOFs), has attracted great interest in recent years. However, rapid combination of the photoinduced carriers limits its further application. Here, we designed a facile precipitation-photoreduction method to post-synthetically decorate Ag/AgCl on the surface of UiO-66-NH2 and form a heterostructure. Metallic Ag can not only transmit electrons between UiO-66-NH2 and AgCl but also absorb visible light, because of the surface plasmon resonance (SPR) effect. The rhodamine B photodegradation rate of UiO-66-NH2/Ag/AgCl (16.2 wt.% Ag) is about 10 and 4 times those of UiO-66-NH2 and Ag/AgCl, respectively. The SPR effect of Ag NPs and the formation of a heterostructure synergistically increase the absorbability of visible light, accelerate the separation of photoinduced charges, and promote the formation of superoxide radicals. We expect that our work could provide a new viewpoint for constructing efficient MOF-based photocatalytic systems.展开更多
Activated carbon/nanosized CdS/chitosan(AC/n-CdS/CS) composites as adsorbent and photoactive catalyst were prepared under low temperature(≤60 ℃) and ambient pressure.Methyl orange(MO) was chosen as a model pollutant...Activated carbon/nanosized CdS/chitosan(AC/n-CdS/CS) composites as adsorbent and photoactive catalyst were prepared under low temperature(≤60 ℃) and ambient pressure.Methyl orange(MO) was chosen as a model pollutant to evaluate synergistic effect of adsorption and photocatalytic decolorization by this innovative photocatalyst under visible light irradiation.Effects of various parameters such as catalyst amount,initial MO concentration,solution pH and reuse of catalyst on the decolorization of MO were investigated to optimize operational conditions.The decolorization of MO catalyzed by AC/n-CdS/CS fits the Langmuir-Hinshelwood kinetics model,and a surface reaction,where the dyes are absorbed,is the controlling step of the process.Decolorization efficiency of MO is improved with the increase in catalyst amount within a certain range.The photodecolorization of MO is more efficient in acidic media than alkaline media.The decolorization efficiency of MO is still higher than 84% after five cycles and 60 min under visible light irradiation,which confirms the reusability of AC/n-CdS/CS composite catalyst.展开更多
Bandgap engineering by doping and co‐catalyst loading are two primary approaches to designing efficient photocatalysts by promoting visible‐light absorption and charge separation,respectively.Shifting of the TiO2con...Bandgap engineering by doping and co‐catalyst loading are two primary approaches to designing efficient photocatalysts by promoting visible‐light absorption and charge separation,respectively.Shifting of the TiO2conduction band edge is frequently applied to increase visible‐light absorption but also lowers the reductive properties of photo‐excited electrons.Herein,we report a visible‐light‐driven photocatalyst based on valance band edge control induced by oxygen excess defects and modification with a CuxO electron transfer co‐catalyst.The CuxO grafted oxygen‐rich TiO2microspheres were prepared by ultrasonic spray pyrolysis of the peroxotitanate precursor followed by a wet chemical impregnated treatment.We found that oxygen excess defects in TiO2shifted the valence band maximum upward and improved the visible‐light absorption.The CuxO grafted onto the surface acted as a co‐catalyst that efficiently reduced oxygen molecules to active intermediates(i.e.,O2??radial and H2O2),thus consuming the photo‐generated electrons.Consequently,the CuxO grafted oxygen‐rich TiO2microspheres achieved a photocatalytic activity respectively8.6,13.0and11.0as times high as those of oxygen‐rich TiO2,normal TiO2and CuxO grafted TiO2,for degradation of gaseous acetaldehyde under visible‐light irradiation.Our results suggest that high visible‐light photocatalytic efficiency can be achieved by combining oxygen excess defects to improve visible‐light absorption together with a CuxO electron transfer co‐catalyst.These findings provide a new approach to developing efficient heterojunction photocatalysts.展开更多
Lanthanum and nitrogen co-doped SrTiO3 was synthesized using polymerized complex method with Ti(OC3H7)4, SrCl2·6H2O and La(NO3)3·6H2O as starting materials followed by calcinations in NH3. Ethylene glycol an...Lanthanum and nitrogen co-doped SrTiO3 was synthesized using polymerized complex method with Ti(OC3H7)4, SrCl2·6H2O and La(NO3)3·6H2O as starting materials followed by calcinations in NH3. Ethylene glycol and anhydrous citric acid were used as the precursors of synthesis. The samples were characterized using XRD, TEM, DRS, BET, EDX and XPS. The cubic-perovskite type of La/N co-doped SrTiO3 nanoparticle could be successfully synthesized. The photocatalytic activity of SrTiO3 for DeNOx ability in visible light region (λ > 510 nm) could be improved by co-doping of La3+ and N3_. The high visible light photocatalytic activity of this substance was caused by a narrow band gap energy that enables to absorb visible light.展开更多
In this work, we designed and synthesized cationic carbon dots(CDs) with a size distribution of 1.6–3.7 nm, which exhibited dark blue fluorescence in the aqueous solution. Based on its excellent luminescence properti...In this work, we designed and synthesized cationic carbon dots(CDs) with a size distribution of 1.6–3.7 nm, which exhibited dark blue fluorescence in the aqueous solution. Based on its excellent luminescence properties, we used it as an energy donor to construct a sequential artificial light-harvesting system(LHS) by employing the energy-matching dyes eosin Y disodium salt(EY) and sulforhodamine101(SR101), which could regulate the white light emission(Commission Internationale de l'Eclairage(CIE) coordinate:(0.30, 0.31)) with the energy transfer efficiency(ΦET) of 53.9% and 20.0%. Moreover, a single-step artificial LHS with white light emission(0.32, 0.28) can be constructed directly using CDs and dye solvent 43(SR) with ΦETand antenna effect(AE) of 48.8% and 6.5, respectively. More importantly,CDs-based artificial LHSs were firstly used in photocatalytic of α-bromoacetophenone, with a yield of90%. This work not only provides a new strategy for constructing CDs-based LHSs, but also opens up a new application for further applying the energy harvested in CDs-based LHSs to the field of the aqueous solution photocatalysis.展开更多
Fe_(3)O_(4)and Cu_(2)O were successively immobilized on alkali-treated straw,and the magnetically separable straw@Fe_(3)O_(4)/Cu_(2)O composite was obtained.The straw@Fe_(3)O_(4)/Cu_(2)O was characterized by Fourier t...Fe_(3)O_(4)and Cu_(2)O were successively immobilized on alkali-treated straw,and the magnetically separable straw@Fe_(3)O_(4)/Cu_(2)O composite was obtained.The straw@Fe_(3)O_(4)/Cu_(2)O was characterized by Fourier transform infrared spectroscopy,X-ray diffraction,scanning electron microscopy,X-ray photoelectron spectroscopy and vibrating sample magnetometry,respectively.Photocatalytic performance of the straw@Fe_(3)O_(4)/Cu_(2)O was evaluated by measuring the degradation of methyl orange(MO)under irradiation of visible light.The introduction of Fe3O4 not only endowed the straw@Fe_(3)O_(4)/Cu_(2)O with magnetic separation feature but also significantly enhanced photocatalytic activity because Fe3O4 could prevent recombination of hole-electron pairs.The active species capture experiment showed that holes(h+),hydroxyl(∙OH)and superoxide(∙O2ˉ)radicals all took part in the MO degradation.In addition,the photocatalytic mechanism of straw@Fe_(3)O_(4)/Cu_(2)O was proposed based on the experimental results.After five cycles for the photodegradation of MO,the straw@Fe_(3)O_(4)/Cu_(2)O still displayed good photocatalytic activity,suggesting that the as-prepared composite had great potential for practical use in wastewater treatment.展开更多
In order to develop the high photocatalytic activity of TiO2 under visible light as that under ultraviolet light and make it easy to be separated from treated liquor, a visible light response and spherical activated c...In order to develop the high photocatalytic activity of TiO2 under visible light as that under ultraviolet light and make it easy to be separated from treated liquor, a visible light response and spherical activated carbon （SAC） supported photocatalyst doped with upconversion luminescence agent Er3＋：YAlO3 was prepared by immobilizing Er3＋：YAlO3/TiO2, which was obtained by combination of Er3＋：YAlO3 and TiO2 using sol-gel method, on the surface of SAC. The crystal phase composition, surface structure and element distribution, and light absorption of the new photocatalysts were examined by X-ray diffraction （XRD）, energy dispersive X-ray spectra （EDS） analysis, scanning electron microscopy （SEM） and fluorescence spectra analysis （FSA）. The photocatalytic oxidation activity of the photocatalysts was also evaluated by the photodegradation of methyl orange （MO） in aqueous solution under visible light irradiation from a LED lamp （λ400 nm）. The results showed that Er3＋：YAlO3 could perform as the upconversion luminescence agent which converts the visible light up to ultraviolet light. The Er3＋：YAlO3/TiO2 calcinated at 700 °C revealed the highest photocatalytic activity. The apparent reaction rate constant could reach 0.0197 min-1 under visible light irradiation.展开更多
Heterostructured BiOI@La（OH）3 nanorod photocatalysts were prepared by a facile chemical impregnation method.The enhanced visible light absorption and charge carrier separation can be simultaneously realized after th...Heterostructured BiOI@La（OH）3 nanorod photocatalysts were prepared by a facile chemical impregnation method.The enhanced visible light absorption and charge carrier separation can be simultaneously realized after the introduction of BiOI particles into La（OH）3 nanorods.The BiOI@La（OH）3 composites were applied for visible light photocatalytic oxidization of NO in air and exhibited an enhanced activity compared with BiOI and pure La（OH）3 nanorods.The results show that the energy levels between the La（OH）3 and BiOI phases matched well with each other,thus forming a heterojunctioned BiOI@La（OH）3 structure.This band structure matching could promote the separation and transfer of photoinduced electron-hole pairs at the interface,resulting in enhanced photocatalytic performance under visible light irradiation.The photocatalytic performance of BiOI@La（OH）3 is shown to be dependent on the mass ratio of BiOI to La（OH）3.The highest photocatalytic performance can be achieved when the mass ratio of BiOI to La（OH）3 is controlled at 1.5.A further increase of the mass ratio of BiOI weakened the redox abilities of the photogenerated charge carriers.A new photocatalytic mechanism for BiOI@La（OH）3 heterostructures is proposed,which is directly related to the efficient separation of photogenerated charge carriers by the heterojunction.Importantly,the as-prepared BiOI@La（OH）3 heterostructures exhibited a high photochemical stability after multiple reaction runs.Our findings demonstrate that BiOI is an effective component for the formation of a heterostructure with the properties of a wide bandgap semiconductor,which is of great importance for extending the light absorption and photocatalytic activity of wide bandgap semiconductors into visible light region.展开更多
Photocatalysis is regarded as an ideal technology for solving the urgent environmental and energy issues that we face today.Among the reported photocatalysts,molybdenum disulfide（MoS2） is very promising for applicat...Photocatalysis is regarded as an ideal technology for solving the urgent environmental and energy issues that we face today.Among the reported photocatalysts,molybdenum disulfide（MoS2） is very promising for applications in hydrogen production and pollutant photodegradation.However,its lack of active sites and the difficulty of recovering catalysts in powder form have hindered its wide application.Here,we report the successful preparation of a macroscopic visible-light responsive MoS2/reduced graphene oxide（MoS2/RGO） aerogel.The obtained MoS2/RGO aerogel exhibits enhanced photocatalytic activity towards hydrogen production and photoreduction of Cr（Ⅵ） in comparison with the MoS2 powder.In addition,the low density（56.1 mg/cm^3） of the MoS2/RGO aerogel enables it to be used as an efficient adsorption material for organic pollutants.Our results demonstrate that this very promising multifunctional aerogel has potential applications in environmental remediation and clean energy production.展开更多
Extensive work on a Cu-modified TiO_(2) photocatalyst for CO_(2) reduction under visible light irradiation was conducted. The structure of the copper cocatalyst was established using UV-vis diff use refl ectance spect...Extensive work on a Cu-modified TiO_(2) photocatalyst for CO_(2) reduction under visible light irradiation was conducted. The structure of the copper cocatalyst was established using UV-vis diff use refl ectance spectroscopy, high-resolution transmis- sion electron microscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy. It was found that copper exists in different states (Cu 0 , Cu^(+) , and Cu^(2+) ), the content of which depends on the TiO_(2) calcination temperature and copper loading. The optimum composition of the cocatalyst has a photocatalyst based on TiO_(2) calcined at 700℃ and modified with 5 wt% copper, the activity of which is 22 μmol/(h·g cat ) (409 nm). Analysis of the photocatalysts after the photocatalytic reaction disclosed that the copper metal on the surface of the calcined TiO_(2) was gradually converted into Cu_(2) O during the photocatalytic reaction. Meanwhile, the metallic copper on the surface of the noncalcined TiO_(2) did not undergo any trans- formation during the reaction.展开更多
基金supported by the National Natural Science Foundation of China(21676182)the National Basic Research Program of China(973 Program,2014CB932403)the Program for Introducing Talents of Discipline to Universities of China(B06006)
文摘UiO-66-NH2, as typical visible light responsive Zr-based metal-organic frameworks (MOFs), has attracted great interest in recent years. However, rapid combination of the photoinduced carriers limits its further application. Here, we designed a facile precipitation-photoreduction method to post-synthetically decorate Ag/AgCl on the surface of UiO-66-NH2 and form a heterostructure. Metallic Ag can not only transmit electrons between UiO-66-NH2 and AgCl but also absorb visible light, because of the surface plasmon resonance (SPR) effect. The rhodamine B photodegradation rate of UiO-66-NH2/Ag/AgCl (16.2 wt.% Ag) is about 10 and 4 times those of UiO-66-NH2 and Ag/AgCl, respectively. The SPR effect of Ag NPs and the formation of a heterostructure synergistically increase the absorbability of visible light, accelerate the separation of photoinduced charges, and promote the formation of superoxide radicals. We expect that our work could provide a new viewpoint for constructing efficient MOF-based photocatalytic systems.
基金Project(21007044) supported by the National Natural Science Foundation of ChinaProject(20050532009) supported by the Doctoral Foundation of Ministry of Education of China
文摘Activated carbon/nanosized CdS/chitosan(AC/n-CdS/CS) composites as adsorbent and photoactive catalyst were prepared under low temperature(≤60 ℃) and ambient pressure.Methyl orange(MO) was chosen as a model pollutant to evaluate synergistic effect of adsorption and photocatalytic decolorization by this innovative photocatalyst under visible light irradiation.Effects of various parameters such as catalyst amount,initial MO concentration,solution pH and reuse of catalyst on the decolorization of MO were investigated to optimize operational conditions.The decolorization of MO catalyzed by AC/n-CdS/CS fits the Langmuir-Hinshelwood kinetics model,and a surface reaction,where the dyes are absorbed,is the controlling step of the process.Decolorization efficiency of MO is improved with the increase in catalyst amount within a certain range.The photodecolorization of MO is more efficient in acidic media than alkaline media.The decolorization efficiency of MO is still higher than 84% after five cycles and 60 min under visible light irradiation,which confirms the reusability of AC/n-CdS/CS composite catalyst.
基金supported by the National Natural Science Foundation of China(51072032,51372036,51702235)~~
文摘Bandgap engineering by doping and co‐catalyst loading are two primary approaches to designing efficient photocatalysts by promoting visible‐light absorption and charge separation,respectively.Shifting of the TiO2conduction band edge is frequently applied to increase visible‐light absorption but also lowers the reductive properties of photo‐excited electrons.Herein,we report a visible‐light‐driven photocatalyst based on valance band edge control induced by oxygen excess defects and modification with a CuxO electron transfer co‐catalyst.The CuxO grafted oxygen‐rich TiO2microspheres were prepared by ultrasonic spray pyrolysis of the peroxotitanate precursor followed by a wet chemical impregnated treatment.We found that oxygen excess defects in TiO2shifted the valence band maximum upward and improved the visible‐light absorption.The CuxO grafted onto the surface acted as a co‐catalyst that efficiently reduced oxygen molecules to active intermediates(i.e.,O2??radial and H2O2),thus consuming the photo‐generated electrons.Consequently,the CuxO grafted oxygen‐rich TiO2microspheres achieved a photocatalytic activity respectively8.6,13.0and11.0as times high as those of oxygen‐rich TiO2,normal TiO2and CuxO grafted TiO2,for degradation of gaseous acetaldehyde under visible‐light irradiation.Our results suggest that high visible‐light photocatalytic efficiency can be achieved by combining oxygen excess defects to improve visible‐light absorption together with a CuxO electron transfer co‐catalyst.These findings provide a new approach to developing efficient heterojunction photocatalysts.
文摘Lanthanum and nitrogen co-doped SrTiO3 was synthesized using polymerized complex method with Ti(OC3H7)4, SrCl2·6H2O and La(NO3)3·6H2O as starting materials followed by calcinations in NH3. Ethylene glycol and anhydrous citric acid were used as the precursors of synthesis. The samples were characterized using XRD, TEM, DRS, BET, EDX and XPS. The cubic-perovskite type of La/N co-doped SrTiO3 nanoparticle could be successfully synthesized. The photocatalytic activity of SrTiO3 for DeNOx ability in visible light region (λ > 510 nm) could be improved by co-doping of La3+ and N3_. The high visible light photocatalytic activity of this substance was caused by a narrow band gap energy that enables to absorb visible light.
基金This work was supported by the National Natural Science Foundation of China （Grant Nos. 41172110 and 61107090） and Shandong Provincial Natural Science Foundation （Grant No. ZR2011BZ007）.
基金the financial support from the National Natural Science Foundation of China (Nos.52205210 and 22002075)the Natural Science Foundation of Shandong Province (Nos.ZR2020MB018 and ZR2022QE033)。
文摘In this work, we designed and synthesized cationic carbon dots(CDs) with a size distribution of 1.6–3.7 nm, which exhibited dark blue fluorescence in the aqueous solution. Based on its excellent luminescence properties, we used it as an energy donor to construct a sequential artificial light-harvesting system(LHS) by employing the energy-matching dyes eosin Y disodium salt(EY) and sulforhodamine101(SR101), which could regulate the white light emission(Commission Internationale de l'Eclairage(CIE) coordinate:(0.30, 0.31)) with the energy transfer efficiency(ΦET) of 53.9% and 20.0%. Moreover, a single-step artificial LHS with white light emission(0.32, 0.28) can be constructed directly using CDs and dye solvent 43(SR) with ΦETand antenna effect(AE) of 48.8% and 6.5, respectively. More importantly,CDs-based artificial LHSs were firstly used in photocatalytic of α-bromoacetophenone, with a yield of90%. This work not only provides a new strategy for constructing CDs-based LHSs, but also opens up a new application for further applying the energy harvested in CDs-based LHSs to the field of the aqueous solution photocatalysis.
基金Science and Technology Project from Ministry of Housing and Urban-Rural Development of the People’s Republic of China(No.2014-K7-007)。
文摘Fe_(3)O_(4)and Cu_(2)O were successively immobilized on alkali-treated straw,and the magnetically separable straw@Fe_(3)O_(4)/Cu_(2)O composite was obtained.The straw@Fe_(3)O_(4)/Cu_(2)O was characterized by Fourier transform infrared spectroscopy,X-ray diffraction,scanning electron microscopy,X-ray photoelectron spectroscopy and vibrating sample magnetometry,respectively.Photocatalytic performance of the straw@Fe_(3)O_(4)/Cu_(2)O was evaluated by measuring the degradation of methyl orange(MO)under irradiation of visible light.The introduction of Fe3O4 not only endowed the straw@Fe_(3)O_(4)/Cu_(2)O with magnetic separation feature but also significantly enhanced photocatalytic activity because Fe3O4 could prevent recombination of hole-electron pairs.The active species capture experiment showed that holes(h+),hydroxyl(∙OH)and superoxide(∙O2ˉ)radicals all took part in the MO degradation.In addition,the photocatalytic mechanism of straw@Fe_(3)O_(4)/Cu_(2)O was proposed based on the experimental results.After five cycles for the photodegradation of MO,the straw@Fe_(3)O_(4)/Cu_(2)O still displayed good photocatalytic activity,suggesting that the as-prepared composite had great potential for practical use in wastewater treatment.
基金Projects (50908096, 50908097) supported by the National Natural Science Foundation of ChinaProject (20100471251) supported by China Postdoctoral Science Foundation
文摘In order to develop the high photocatalytic activity of TiO2 under visible light as that under ultraviolet light and make it easy to be separated from treated liquor, a visible light response and spherical activated carbon （SAC） supported photocatalyst doped with upconversion luminescence agent Er3＋：YAlO3 was prepared by immobilizing Er3＋：YAlO3/TiO2, which was obtained by combination of Er3＋：YAlO3 and TiO2 using sol-gel method, on the surface of SAC. The crystal phase composition, surface structure and element distribution, and light absorption of the new photocatalysts were examined by X-ray diffraction （XRD）, energy dispersive X-ray spectra （EDS） analysis, scanning electron microscopy （SEM） and fluorescence spectra analysis （FSA）. The photocatalytic oxidation activity of the photocatalysts was also evaluated by the photodegradation of methyl orange （MO） in aqueous solution under visible light irradiation from a LED lamp （λ400 nm）. The results showed that Er3＋：YAlO3 could perform as the upconversion luminescence agent which converts the visible light up to ultraviolet light. The Er3＋：YAlO3/TiO2 calcinated at 700 °C revealed the highest photocatalytic activity. The apparent reaction rate constant could reach 0.0197 min-1 under visible light irradiation.
基金supported by the National Key Research and Development Project (2016YFC0204702)the National Natural Science Foundation of China (51478070, 21501016, 51108487)+2 种基金the Innovative Research Team of Chongqing (CXTDG201602014)the Natural Science Foundation of Chongqing (cstc2016jcyjA0481)Youth Innovation Promotion Association of Chinese Academy of Sciences (2015316)~~
文摘Heterostructured BiOI@La（OH）3 nanorod photocatalysts were prepared by a facile chemical impregnation method.The enhanced visible light absorption and charge carrier separation can be simultaneously realized after the introduction of BiOI particles into La（OH）3 nanorods.The BiOI@La（OH）3 composites were applied for visible light photocatalytic oxidization of NO in air and exhibited an enhanced activity compared with BiOI and pure La（OH）3 nanorods.The results show that the energy levels between the La（OH）3 and BiOI phases matched well with each other,thus forming a heterojunctioned BiOI@La（OH）3 structure.This band structure matching could promote the separation and transfer of photoinduced electron-hole pairs at the interface,resulting in enhanced photocatalytic performance under visible light irradiation.The photocatalytic performance of BiOI@La（OH）3 is shown to be dependent on the mass ratio of BiOI to La（OH）3.The highest photocatalytic performance can be achieved when the mass ratio of BiOI to La（OH）3 is controlled at 1.5.A further increase of the mass ratio of BiOI weakened the redox abilities of the photogenerated charge carriers.A new photocatalytic mechanism for BiOI@La（OH）3 heterostructures is proposed,which is directly related to the efficient separation of photogenerated charge carriers by the heterojunction.Importantly,the as-prepared BiOI@La（OH）3 heterostructures exhibited a high photochemical stability after multiple reaction runs.Our findings demonstrate that BiOI is an effective component for the formation of a heterostructure with the properties of a wide bandgap semiconductor,which is of great importance for extending the light absorption and photocatalytic activity of wide bandgap semiconductors into visible light region.
基金supported by the National Natural Science Foundation of China (U1232119, 21403172)the Sichuan Youth Science and Technology Foundation (2013JQ0034, 2014JQ0017)the Innovative Research Team of Sichuan Province (2016TD0011)~~
文摘Photocatalysis is regarded as an ideal technology for solving the urgent environmental and energy issues that we face today.Among the reported photocatalysts,molybdenum disulfide（MoS2） is very promising for applications in hydrogen production and pollutant photodegradation.However,its lack of active sites and the difficulty of recovering catalysts in powder form have hindered its wide application.Here,we report the successful preparation of a macroscopic visible-light responsive MoS2/reduced graphene oxide（MoS2/RGO） aerogel.The obtained MoS2/RGO aerogel exhibits enhanced photocatalytic activity towards hydrogen production and photoreduction of Cr（Ⅵ） in comparison with the MoS2 powder.In addition,the low density（56.1 mg/cm^3） of the MoS2/RGO aerogel enables it to be used as an efficient adsorption material for organic pollutants.Our results demonstrate that this very promising multifunctional aerogel has potential applications in environmental remediation and clean energy production.
基金supported by Russian Science Foundation (No.#21-73-10235)
文摘Extensive work on a Cu-modified TiO_(2) photocatalyst for CO_(2) reduction under visible light irradiation was conducted. The structure of the copper cocatalyst was established using UV-vis diff use refl ectance spectroscopy, high-resolution transmis- sion electron microscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy. It was found that copper exists in different states (Cu 0 , Cu^(+) , and Cu^(2+) ), the content of which depends on the TiO_(2) calcination temperature and copper loading. The optimum composition of the cocatalyst has a photocatalyst based on TiO_(2) calcined at 700℃ and modified with 5 wt% copper, the activity of which is 22 μmol/(h·g cat ) (409 nm). Analysis of the photocatalysts after the photocatalytic reaction disclosed that the copper metal on the surface of the calcined TiO_(2) was gradually converted into Cu_(2) O during the photocatalytic reaction. Meanwhile, the metallic copper on the surface of the noncalcined TiO_(2) did not undergo any trans- formation during the reaction.
