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Kazunari Domen - One of the best experts on this subject based on the ideXlab platform.
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Effect of Hydrogen and Oxygen Evolution Cocatalysts on Photocatalytic Activity of GaN:ZnO
European Journal of Inorganic Chemistry, 2013Co-Authors: Anke Xiong, Taizo Yoshinaga, Masaki Takashima, Toru Setoyama, Kazuhiko Maeda, Takashi Hisatomi, Toshiharu Teranishi, Takahiro Ikeda, Kazunari DomenAbstract:The coloading effect of H2 and O2 evolution Cocatalysts on the overall water splitting reaction was investigated using a solid solution of GaN and ZnO (hereafter termed GaN:ZnO) as a photocatalyst. GaN:ZnO was modified with nanoparticulate Mn3O4, RuO2, and IrO2 as O2 evolution Cocatalysts and with core/shell-type Rh/Cr2O3 composites as H2 evolution Cocatalysts. The photocatalytic activity of the coloaded samples for overall water splitting was higher than that of the samples modified with either of the O2 or H2 evolution Cocatalysts alone. The activity enhancement induced by coloading was comparable for the three O2 evolution Cocatalysts investigated at the optimized loading amounts. Loading of a more efficient Rh/Cr2O3 cocatalyst prepared by adsorption of Rh nanoparticles further improved the photocatalytic activity. It was concluded that a simultaneous improvement in both oxidation and reduction reactions was effective at enhancing the photocatalytic activity of GaN:ZnO, whereas the reduction reactions limited the overall reaction rate of the coloaded system more significantly.
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visible light driven nonsacrificial water oxidation over tungsten trioxide powder modified with two different Cocatalysts
Energy and Environmental Science, 2012Co-Authors: Su Su Khine, Kazuhiko Maeda, Ryu Abe, Kazunari DomenAbstract:Tungsten trioxide (WO3) powder was studied as a photocatalyst for water oxidation under visible light (λ > 420 nm). WO3 modified with nanoparticulate Pt species (more specifically, PtOx) as Cocatalysts is capable of photocatalyzing water oxidation under visible light in the presence of iodate (IO3−) ions as an electron acceptor under near-neutral pH conditions (pH ≈ 5.9). When PtOx/WO3 was further modified with a very small amount (0.001 wt%) of a metal oxide (e.g., MnOx, CoOx, RuO2 or IrO2) as a secondary cocatalyst, the water oxidation activity was improved. Among the metal oxide Cocatalysts examined, RuO2 was found to give the highest performance, with an apparent quantum yield of 14.4% at 420 nm. The results of photocatalytic reactions and photoelectrochemical analyses suggest that the main roles of the loaded PtOx and RuO2 on WO3 are to promote the reduction of IO3− and water oxidation, respectively.
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photocatalytic water splitting using modified gan zno solid solution under visible light long time operation and regeneration of activity
Journal of the American Chemical Society, 2012Co-Authors: Tomoyuki Ohno, Kazuhiko Maeda, Takashi Hisatomi, Kazunari DomenAbstract:Overall water splitting using GaN:ZnO solid solution photocatalyst modified with Rh2–yCryO3 nanoparticles as H2 evolution Cocatalysts under visible light (400 < λ < 500 nm) was examined with respect to long-term durability and regeneration of photocatalytic activity. The rate of visible light water splitting remained unchanged for 3 months (2160 h), producing H2 and O2 continuously at a stoichiometric amount. After 6 months of operation, a 50% loss of the initial activity occurred. Regeneration treatment of deactivated catalysts was attempted by reloading the Rh2–yCryO3 cocatalyst. The degree of activity regeneration depended on the reloading amount. Up to 80% of the initial activity for H2 evolution could be recovered under optimal treatment conditions. It was also found that deactivation of GaN:ZnO was suppressed to some extent by prior coloading of an O2 evolution cocatalyst, which helped to suppress oxidative decomposition of GaN:ZnO by valence band holes, thereby improving the durability.
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photocatalytic water splitting recent progress and future challenges
Journal of Physical Chemistry Letters, 2010Co-Authors: Kazuhiko Maeda, Kazunari DomenAbstract:Water splitting to form hydrogen and oxygen using solar energy in the presence of semiconductor photocatalysts has long been studied as a potential means of clean, large-scale fuel production. In general, overall water splitting can be achieved when a photocatalyst is modified with a suitable cocatalyst. It is therefore important to develop both photocatalysts and Cocatalysts. In the past five years, there has been significant progress in water splitting photocatalysis, especially in the development of Cocatalysts and related physical and materials chemistry. This work describes the state of the art and future challenges in photocatalytic water splitting, with a focus on the recent progress of our own research.
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photocatalytic hydrogen evolution from water using copper gallium sulfide under visible light irradiation
Journal of Physical Chemistry C, 2010Co-Authors: Masashi Tabata, Takahiro Ishihara, Kazuhiko Maeda, Tsutomu Minegishi, Tsuyoshi Takata, Kazunari DomenAbstract:Copper gallium sulfide with a chalcopyrite-type structure (CuGa3S5) and a band gap of ca. 2.4 eV was prepared by a solid-state reaction. The as-prepared CuGa3S5 exhibited photocatalytic hydrogen evolution activity in an aqueous solution containing Na2S and Na2SO3 as sacrificial electron donors under visible-light irradiation (λ > 420 nm), even without a cocatalyst, such as platinum (Pt). The photocatalytic activity, however, was improved by the deposition of noble metal Cocatalysts. Among the noble metals tested, rhodium (Rh) was found to be the most effective cocatalyst to improve the H2 evolution activity, which was 2.5 times that achieved without a cocatalyst. Dispersion of base sulfides, including nickel sulfide (NiS) and iron sulfide (FeS), into the reactant solution containing CuGa3S5 also increased the activity. The activity under optimized conditions (5.0 wt % NiS/CuGa3S5) was 3 times that of a similarly optimized Rh/CuGa3S5. The results of electrochemical measurements and photocatalytic reactions...
Jiaguo Yu - One of the best experts on this subject based on the ideXlab platform.
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Dual Cocatalysts in TiO2 Photocatalysis.
Advanced Materials, 2019Co-Authors: Aiyun Meng, Bei Cheng, Liuyang Zhang, Jiaguo YuAbstract:: Semiconductor photocatalysis is recognized as a promising strategy to simultaneously address energy needs and environmental pollution. Titanium dioxide (TiO2 ) has been investigated for such applications due to its low cost, nontoxicity, and high chemical stability. However, pristine TiO2 still suffers from low utilization of visible light and high photogenerated-charge-carrier recombination rate. Recently, TiO2 photocatalysts modified by dual Cocatalysts with different functions have attracted much attention due to the extended light absorption, enhanced reactant adsorption, and promoted charge-carrier-separation efficiency granted by various Cocatalysts. Recent progress on the component and structural design of dual Cocatalysts in TiO2 photocatalysts is summarized. Depending on their components, dual Cocatalysts decorated on TiO2 photocatalysts can be divided into the following categories: bimetallic Cocatalysts, metal-metal oxide/sulfide Cocatalysts, metal-graphene Cocatalysts, and metal oxide/sulfide-graphene Cocatalysts. Depending on their architecture, they can be categorized into randomly deposited binary Cocatalysts, facet-dependent selective-deposition binary Cocatalysts, and core-shell structural binary Cocatalysts. Concluding perspectives on the challenges and opportunities for the further exploration of dual cocatalyst-modified TiO2 photocatalysts are presented.
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enhanced photocatalytic h 2 production activity of anatase tio 2 nanosheet by selectively depositing dual Cocatalysts on 101 and 001 facets
Applied Catalysis B-environmental, 2016Co-Authors: Aiyun Meng, Difa Xu, Jiaguo Yu, Bei Cheng, Jun ZhangAbstract:Abstract The photocatalytic hydrogen production using solar energy through water splitting has received great attention due to the increasingly serious energy crisis. Herein, we report the controlled preparation of anatase TiO 2 nanosheet photocatalyst by selectively depositing Co 3 O 4 nanoparticles (NPs) as water oxidation cocatalyst (WOC) and Pt NPs as water reduction cocatalyst (WRC) on {001} and {101} facets, respectively, using a two-step photodeposition method. The prepared TiO 2 -Co 3 O 4 -Pt composite photocatalyst exhibits a greatly enhanced photocatalytic H 2 -production activity at the optimal weight percentage of Co 3 O 4 and Pt (both 1.0 wt%), exceeding that of TiO 2 nanosheet deposited with single Co 3 O 4 or Pt cocatalyst by 9.4 and 1.8 times, respectively. The enhanced H 2 -production activity is due to the synergetic effect of surface heterojunction between {001} and {101} facets and selective deposition of Co 3 O 4 and Pt dual-Cocatalysts at {001} and{101} facets, respectively. The former is beneficial for the transfer and separation of charge carriers, the latter can reduce the recombination rate of photogenerated electrons and holes and also catalyze the redox reactions. This work will provide a new route for the rational design and fabrication of highly efficient photocatalysts with dual-Cocatalysts through selective surface deposition.
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amorphous molybdenum sulfide as highly efficient electron cocatalyst for enhanced photocatalytic h2 evolution
Applied Catalysis B-environmental, 2016Co-Authors: Huogen Yu, Ping Wang, Pian Xiao, Jiaguo YuAbstract:Abstract Exploiting novel and high-performance electron-Cocatalysts without noble metallic element is of great significance for photocatalytic H 2 -evolution reaction. Molybdenum sulfide is one of the promising candidates of such electron-Cocatalysts, but its present performance is intrinsically restrained by the scarce active sites of unsaturated S atoms. In this study, amorphous MoS x (a-MoS x ) nanoparticles were directly anchored on the g-C 3 N 4 surface by an adsorption-in situ transformation method with the aim of improving photocatalytic H 2 -evolution activity. It was found that compared with the crystalline molybdenum sulfide (c-MoS 2 ), the a-MoS x cocatalyst clearly exhibited more unsaturated active S atoms due to its highly irregular arrangement structure. Photocatalytic experimental results suggested that the H 2 -evolution activity of g-C 3 N 4 photocatalyst could be obviously improved by loading a-MoS x cocatalyst, which is obviously higher than that of unmodified g-C 3 N 4 and c-MoS 2 /g-C 3 N 4 . More importantly, in addition to the g-C 3 N 4 , the amorphous MoS x could also work as the efficient electron cocatalyst to greatly enhance the photocatalytic performance of conventional H 2 -evolution materials such as TiO 2 (a typical UV-light photocatalyst) and CdS (a typical Vis-light photocatalyst). On the basis of the present results, an electron-cocatalyst mechanism of amorphous MoS x was proposed to account for the improved photocatalytic H 2 -evolution activity, namely, the amorphous MoS x can provide more unsaturated active S atoms as the efficient active sites to rapidly capture protons from solution, and then promote the direct reduction of H + to H 2 by photogenerated electrons. Considering its low cost and high efficiency, the amorphous MoS x cocatalyst would have great potential for the development of high-performance photocatalytic materials used in various fields.
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cu ii as a general cocatalyst for improved visible light photocatalytic performance of photosensitive ag based compounds
Journal of Physical Chemistry C, 2014Co-Authors: Ping Wang, Panpan Wu, Huogen Yu, Xuefei Wang, Jiaguo YuAbstract:Usually, cocatalyst modification of photocatalysts is an efficient approach to enhance the photocatalytic performance by promoting effective separation of photogenerated electrons and holes. It is highly required to explore new and effective Cocatalysts to further enhance the photocatalytic performance of photocatalytic materials. In the present work, Cu(II) cocatalyst was successfully loaded on the surface of various Ag-based compounds (such as AgCl, Ag3PO4, AgBr, AgI, Ag2CO3, and Ag2O) by a simple impregnation route, and their photocatalytic activity of Cu(II)/Ag-based photocatalysts was evaluated by the photocatalytic decolorization of methyl orange and photocatalytic decomposition of phenol solution under visible-light illumination. As one of the typical photosensitive Ag-based compounds, the photocatalytic activity of AgCl could be greatly improved by optimizing the amount of Cu(II) cocatalyst, and the highest photocatalytic performance of the resulted Cu(II)/AgCl was higher than that of the unmodifi...
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enhanced photoinduced stability and photocatalytic activity of agbr photocatalyst by surface modification of fe iii cocatalyst
Applied Catalysis B-environmental, 2014Co-Authors: Huogen Yu, Linli Xu, Xuefei Wang, Ping Wang, Jiaguo YuAbstract:Abstract Recently, AgBr material was demonstrated to be a new and efficient visible-light photocatalyst for the decomposition of various organic compounds. Owing to its excellent photosensitive properties, however, AgBr phase is unavoidably decomposed into metallic Ag under visible-light irradiation, resulting in an obvious destroy of its surface structure. In this study, Fe(III) cocatalyst was grafted on the surface of AgBr particles to form Fe(III)/AgBr photocatalysts by an impregnation method and their photocatalytic performance was evaluated by the photocatalytic decolorization of methyl orange solution under visible-light irradiation. It was found that the Fe(III) cluster could act as a new and effective cocatalyst not only to improve the photocatalytic activity of AgBr photocatalyst, but also remarkably enhance the photoinduced stability of photosensitive AgBr. After surface coating by Fe(III) cocatalyst (8.2 at.%), the photocatalytic activity of AgBr photocatalyst can be greatly improved by a factor of 73% even after five cycles of photocatalytic reactions. Simultaneously, the decomposed amount of AgBr can be significantly deduced from 8.8 at.% to 2.9 at.% by the surface loading of Fe(III) cocatalyst. On the basis of the experimental results, an possible mechanism for the enhanced photocatalytic activity and photoinduced stability of AgBr by Fe(III) cocatalyst was proposed. Compared with the well-known noble metal Cocatalysts (e.g., Pt, Au, Ag), the present abundant and cheap Fe(III) cocatalyst can be regarded as one of the ideal cocatalyst for the smart design and development of high-performance photocatalytic materials in various potential applications.
Kazuhiko Maeda - One of the best experts on this subject based on the ideXlab platform.
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Effect of Hydrogen and Oxygen Evolution Cocatalysts on Photocatalytic Activity of GaN:ZnO
European Journal of Inorganic Chemistry, 2013Co-Authors: Anke Xiong, Taizo Yoshinaga, Masaki Takashima, Toru Setoyama, Kazuhiko Maeda, Takashi Hisatomi, Toshiharu Teranishi, Takahiro Ikeda, Kazunari DomenAbstract:The coloading effect of H2 and O2 evolution Cocatalysts on the overall water splitting reaction was investigated using a solid solution of GaN and ZnO (hereafter termed GaN:ZnO) as a photocatalyst. GaN:ZnO was modified with nanoparticulate Mn3O4, RuO2, and IrO2 as O2 evolution Cocatalysts and with core/shell-type Rh/Cr2O3 composites as H2 evolution Cocatalysts. The photocatalytic activity of the coloaded samples for overall water splitting was higher than that of the samples modified with either of the O2 or H2 evolution Cocatalysts alone. The activity enhancement induced by coloading was comparable for the three O2 evolution Cocatalysts investigated at the optimized loading amounts. Loading of a more efficient Rh/Cr2O3 cocatalyst prepared by adsorption of Rh nanoparticles further improved the photocatalytic activity. It was concluded that a simultaneous improvement in both oxidation and reduction reactions was effective at enhancing the photocatalytic activity of GaN:ZnO, whereas the reduction reactions limited the overall reaction rate of the coloaded system more significantly.
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visible light driven nonsacrificial water oxidation over tungsten trioxide powder modified with two different Cocatalysts
Energy and Environmental Science, 2012Co-Authors: Su Su Khine, Kazuhiko Maeda, Ryu Abe, Kazunari DomenAbstract:Tungsten trioxide (WO3) powder was studied as a photocatalyst for water oxidation under visible light (λ > 420 nm). WO3 modified with nanoparticulate Pt species (more specifically, PtOx) as Cocatalysts is capable of photocatalyzing water oxidation under visible light in the presence of iodate (IO3−) ions as an electron acceptor under near-neutral pH conditions (pH ≈ 5.9). When PtOx/WO3 was further modified with a very small amount (0.001 wt%) of a metal oxide (e.g., MnOx, CoOx, RuO2 or IrO2) as a secondary cocatalyst, the water oxidation activity was improved. Among the metal oxide Cocatalysts examined, RuO2 was found to give the highest performance, with an apparent quantum yield of 14.4% at 420 nm. The results of photocatalytic reactions and photoelectrochemical analyses suggest that the main roles of the loaded PtOx and RuO2 on WO3 are to promote the reduction of IO3− and water oxidation, respectively.
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photocatalytic water splitting using modified gan zno solid solution under visible light long time operation and regeneration of activity
Journal of the American Chemical Society, 2012Co-Authors: Tomoyuki Ohno, Kazuhiko Maeda, Takashi Hisatomi, Kazunari DomenAbstract:Overall water splitting using GaN:ZnO solid solution photocatalyst modified with Rh2–yCryO3 nanoparticles as H2 evolution Cocatalysts under visible light (400 < λ < 500 nm) was examined with respect to long-term durability and regeneration of photocatalytic activity. The rate of visible light water splitting remained unchanged for 3 months (2160 h), producing H2 and O2 continuously at a stoichiometric amount. After 6 months of operation, a 50% loss of the initial activity occurred. Regeneration treatment of deactivated catalysts was attempted by reloading the Rh2–yCryO3 cocatalyst. The degree of activity regeneration depended on the reloading amount. Up to 80% of the initial activity for H2 evolution could be recovered under optimal treatment conditions. It was also found that deactivation of GaN:ZnO was suppressed to some extent by prior coloading of an O2 evolution cocatalyst, which helped to suppress oxidative decomposition of GaN:ZnO by valence band holes, thereby improving the durability.
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photocatalytic water splitting recent progress and future challenges
Journal of Physical Chemistry Letters, 2010Co-Authors: Kazuhiko Maeda, Kazunari DomenAbstract:Water splitting to form hydrogen and oxygen using solar energy in the presence of semiconductor photocatalysts has long been studied as a potential means of clean, large-scale fuel production. In general, overall water splitting can be achieved when a photocatalyst is modified with a suitable cocatalyst. It is therefore important to develop both photocatalysts and Cocatalysts. In the past five years, there has been significant progress in water splitting photocatalysis, especially in the development of Cocatalysts and related physical and materials chemistry. This work describes the state of the art and future challenges in photocatalytic water splitting, with a focus on the recent progress of our own research.
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photocatalytic hydrogen evolution from water using copper gallium sulfide under visible light irradiation
Journal of Physical Chemistry C, 2010Co-Authors: Masashi Tabata, Takahiro Ishihara, Kazuhiko Maeda, Tsutomu Minegishi, Tsuyoshi Takata, Kazunari DomenAbstract:Copper gallium sulfide with a chalcopyrite-type structure (CuGa3S5) and a band gap of ca. 2.4 eV was prepared by a solid-state reaction. The as-prepared CuGa3S5 exhibited photocatalytic hydrogen evolution activity in an aqueous solution containing Na2S and Na2SO3 as sacrificial electron donors under visible-light irradiation (λ > 420 nm), even without a cocatalyst, such as platinum (Pt). The photocatalytic activity, however, was improved by the deposition of noble metal Cocatalysts. Among the noble metals tested, rhodium (Rh) was found to be the most effective cocatalyst to improve the H2 evolution activity, which was 2.5 times that achieved without a cocatalyst. Dispersion of base sulfides, including nickel sulfide (NiS) and iron sulfide (FeS), into the reactant solution containing CuGa3S5 also increased the activity. The activity under optimized conditions (5.0 wt % NiS/CuGa3S5) was 3 times that of a similarly optimized Rh/CuGa3S5. The results of electrochemical measurements and photocatalytic reactions...
Xuefei Wang - One of the best experts on this subject based on the ideXlab platform.
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enhanced photocatalytic activity and photoinduced stability of ag based photocatalysts the synergistic action of amorphous ti iv and fe iii Cocatalysts
Applied Catalysis B-environmental, 2016Co-Authors: Wuying Chen, Xuefei WangAbstract:Abstract In recent years, Ag-based materials have attracted a great deal of attentions due to their excellent photocatalytic performance. However, the rapid recombination of photogenerated charges and the poor photostability cause an obvious decrease of their photocatalytic performance. In this study, amorphous Ti(IV) as a hole cocatalyst was first successfully loaded on the surface of AgBr photocatalyst by a facile impregnation method. It was found that the photocatalytic activity of AgBr could be greatly improved by a factor of 1.5 when the loading amount of Ti(IV) cocatalyst was 0.05 wt%. Moreover, in addition to the AgBr, the amorphous Ti(IV) could also be used as an effective hole cocatalyst to greatly improve the photocatalytic performance of other Ag-based materials (such as AgCl, AgI, Ag2O, Ag2CO3, and Ag3PO4). However, owing to the rapid transfer of photogenerated holes by Ti(IV) cocatalyst, more photogenerated electrons were accumulated on the conduction band of AgBr, causing an obvious deactivation due to the reduction of surface lattice Ag+ ions to metallic Ag. In this case, after the further surface modification by Fe(III) as an electron cocatalyst, the photoinduced stability and photocatalytic activity of Ti(IV)/AgBr could be significantly enhanced. The possible reason is due to the synergistic action of amorphous Ti(IV) and Fe(III) Cocatalysts, namely, Ti(IV) cocatalyst acts as a hole-capture center to efficiently transfer holes to oxidize organic contaminants, while Fe(III) cocatalyst functions as a reduction active site to reduce oxygen efficiently. Compared with the expensive noble metal cocatalyst (such as Au, Pt, and RuO2), the surface modification by low-cost transition metal Cocatalysts (such as Ti and Fe) is a significant method to develop highly efficient photocatalytic materials.
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highly efficient tio2 single crystal photocatalyst with spatially separated ag and f bi Cocatalysts orientation transfer of photogenerated charges and their rapid interfacial reaction
Journal of Materials Chemistry, 2016Co-Authors: Xuefei WangAbstract:For an efficient photocatalytic system, the rapid orientation transfer of photogenerated electron–hole pairs inside the photocatalyst and their effective interfacial catalytic reactions are significantly critical for achieving a high photocatalytic performance. However, it is quite difficult for a general photocatalyst to realize the crucial functions. In this study, the above idea was easily realized via a coupling strategy of crystal-facet engineering and spatially separated cocatalyst modification, namely, a TiO2 single-crystal photocatalyst with spatially separated Ag and F− bi-Cocatalysts (Ag/F–TiO2). In this case, the F ions (as a hole cocatalyst) and Ag nanoparticles (as an electron cocatalyst) were selectively modified on the hole-rich (001) and electron-rich (101) facets of TiO2 single crystals, respectively. Photocatalytic results demonstrated that the resultant spatially separated Ag/F–TiO2 photocatalyst exhibited an obviously higher photocatalytic performance than pure TiO2, single-cocatalyst modified TiO2 (F–TiO2 and Ag/TiO2) and randomly Ag-deposited TiO2 (Ag/F–TiO2(R)). The main reason for the enhanced photocatalytic activity can be attributed to the excellent synergistic effect of orientation transfer of photogenerated charges and their rapid interfacial reaction via the efficient coupling strategy of crystal-facet engineering and cocatalyst modification, namely, the TiO2 single crystal structure can self-induce the orientation transfer of photogenerated charges to different crystal facets, while the spatially separated Cocatalysts function as the effective active sites for the rapid interfacial catalytic reactions of those spatially separated charges (Ag nanoparticles on the (101) facets work as the active centres for oxygen-reduction reactions, and F ions on the (001) facets serve as the active sites for oxidation reactions of organic substances). The present coupling strategy of crystal-facet engineering and cocatalyst modification may also provide new ideas for the design and preparation of other highly efficient semiconductor photocatalysts.
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synergistic effect of dual electron Cocatalysts for enhanced photocatalytic activity rgo as electron transfer mediator and fe iii as oxygen reduction active site
Scientific Reports, 2015Co-Authors: Jing Tian, Ping Wang, Feng Chen, Xuefei WangAbstract:For a high-performance cocatalyst-modified photocatalyst, an effective interfacial separation of photogenerated electron from its corresponding holes and its following reduction reaction at the active sites are highly required. However, it is difficult for a single-component cocatalyst to simultaneously realize the crucial functions. In this study, an effective interfacial transfer of photogenerated electrons and its following rapid oxygen-reduction can be easily realized in a dual electron-cocatalyst modified Fe(III)/rGO-TiO2 photocatalyst, where the rGO nanosheets function as an electron-transfer mediator for the effective transfer of photogenerated electrons from the TiO2 surface while the Fe(III) cocatalyst serves as an electron-reduction active site to promote the following interfacial oxygen reduction. In this case, the rGO nanosheets were firstly loaded on the TiO2 nanoparticle surface by a hydrothermal method and then the Fe(III) cocatalyst was further modified on the rGO nanosheets by an impregnation method to prepare the Fe(III)/rGO-TiO2 photocatalyst. It was found that the dual electron-cocatalyst modified Fe(III)/rGO-TiO2 photocatalyst showed an obviously higher photocatalytic performance than the naked TiO2 and single-cocatalyst modified photocatalysts (such as Fe(III)/TiO2 and rGO-TiO2) owing to the synergistic effect of rGO and Fe(III) bi-Cocatalysts. The present work can provide some new insights for the smart design of high-efficiency photocatalytic materials.
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cu ii as a general cocatalyst for improved visible light photocatalytic performance of photosensitive ag based compounds
Journal of Physical Chemistry C, 2014Co-Authors: Ping Wang, Panpan Wu, Huogen Yu, Xuefei Wang, Jiaguo YuAbstract:Usually, cocatalyst modification of photocatalysts is an efficient approach to enhance the photocatalytic performance by promoting effective separation of photogenerated electrons and holes. It is highly required to explore new and effective Cocatalysts to further enhance the photocatalytic performance of photocatalytic materials. In the present work, Cu(II) cocatalyst was successfully loaded on the surface of various Ag-based compounds (such as AgCl, Ag3PO4, AgBr, AgI, Ag2CO3, and Ag2O) by a simple impregnation route, and their photocatalytic activity of Cu(II)/Ag-based photocatalysts was evaluated by the photocatalytic decolorization of methyl orange and photocatalytic decomposition of phenol solution under visible-light illumination. As one of the typical photosensitive Ag-based compounds, the photocatalytic activity of AgCl could be greatly improved by optimizing the amount of Cu(II) cocatalyst, and the highest photocatalytic performance of the resulted Cu(II)/AgCl was higher than that of the unmodifi...
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enhanced photoinduced stability and photocatalytic activity of agbr photocatalyst by surface modification of fe iii cocatalyst
Applied Catalysis B-environmental, 2014Co-Authors: Huogen Yu, Linli Xu, Xuefei Wang, Ping Wang, Jiaguo YuAbstract:Abstract Recently, AgBr material was demonstrated to be a new and efficient visible-light photocatalyst for the decomposition of various organic compounds. Owing to its excellent photosensitive properties, however, AgBr phase is unavoidably decomposed into metallic Ag under visible-light irradiation, resulting in an obvious destroy of its surface structure. In this study, Fe(III) cocatalyst was grafted on the surface of AgBr particles to form Fe(III)/AgBr photocatalysts by an impregnation method and their photocatalytic performance was evaluated by the photocatalytic decolorization of methyl orange solution under visible-light irradiation. It was found that the Fe(III) cluster could act as a new and effective cocatalyst not only to improve the photocatalytic activity of AgBr photocatalyst, but also remarkably enhance the photoinduced stability of photosensitive AgBr. After surface coating by Fe(III) cocatalyst (8.2 at.%), the photocatalytic activity of AgBr photocatalyst can be greatly improved by a factor of 73% even after five cycles of photocatalytic reactions. Simultaneously, the decomposed amount of AgBr can be significantly deduced from 8.8 at.% to 2.9 at.% by the surface loading of Fe(III) cocatalyst. On the basis of the experimental results, an possible mechanism for the enhanced photocatalytic activity and photoinduced stability of AgBr by Fe(III) cocatalyst was proposed. Compared with the well-known noble metal Cocatalysts (e.g., Pt, Au, Ag), the present abundant and cheap Fe(III) cocatalyst can be regarded as one of the ideal cocatalyst for the smart design and development of high-performance photocatalytic materials in various potential applications.
Yujie Xiong - One of the best experts on this subject based on the ideXlab platform.
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Hydriding Pd Cocatalysts: An approach to giant enhancement on photocatalytic CO 2 reduction into CH 4
Nano Research, 2017Co-Authors: Yuzhen Zhu, Song Bai, Chao Gao, Shuangming Chen, Ran Long, Li Song, Yujie XiongAbstract:Photocatalytic reduction of CO2 into high value-added CH4 is a promising solution for energy and environmental crises. Integrating semiconductors with Cocatalysts can improve the activities for photocatalytic CO2 reduction; however, most metal Cocatalysts mainly produce CO and H2. Herein, we report a cocatalyst hydridation approach for significantly enhancing the photocatalytic reduction of CO2 into CH4. Hydriding Pd Cocatalysts into PdH0.43 played a dual role in performance enhancement. As revealed by our isotopic labeling experiments, the PdH0.43 hydride Cocatalysts reduced H2 evolution, which suppressed the H2 production and facilitated the conversion of the CO intermediate into the final product: CH4. Meanwhile, hydridation promoted the electron trapping on the Cocatalysts, improving the charge separation. This approach increased the photocatalytic selectivity in CH4 production from 3.2% to 63.6% on Pd{100} and from 15.6% to 73.4% on Pd{111}. The results provide insights into photocatalytic mechanism studies and introduce new opportunities for designing materials towards photocatalytic CO2 conversion.
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surface and interface design in Cocatalysts for photocatalytic water splitting and co2 reduction
RSC Advances, 2016Co-Authors: Lili Wang, Zhengquan Li, Yujie XiongAbstract:Recent advances in photocatalysis highlight the important role of Cocatalysts in improving the solar-to-chemical conversion efficiency for various reactions, such as water splitting and CO2 reduction reactions. Given that Cocatalysts play two important roles, in charge trapping and surface reactions, the rational material design of Cocatalysts would be an effective route in pursuing their maximum contribution to the performance of photocatalysts. In this review, we aim to outline the recent progress of surface and interface design in Cocatalysts for photocatalytic water splitting and CO2 reduction. We first introduce the surface design of Cocatalysts, which enables the enhancement of specific water splitting or CO2 reduction reactions through surface parameter (e.g., the composition, facets and phases) adjustments. We then present key parameters for designing the interface between photocatalyst and cocatalyst, which offer a set of versatile options for tuning the charge transfer to the cocatalyst. Taken together, the surface and interface of Cocatalysts may have synergetic effects on the photocatalytic performance, which are discussed to provide guidance for simultaneously tailoring surface and interface parameters. Finally, we summarize the challenges and opportunities for the surface and interface design of Cocatalysts for the efficient production of solar fuels.
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boosting photocatalytic water splitting interfacial charge polarization in atomically controlled core shell Cocatalysts
Angewandte Chemie, 2015Co-Authors: Li Yang, Junling Lu, Jun Jiang, Chunlei Wang, Yujie XiongAbstract:Platinum is a commonly used cocatalyst for improved charge separation and surface reactions in photocatalytic water splitting. It is envisioned that its practical applications can be facilitated by further reducing the material cost and improving the efficacy of Pt Cocatalysts. In this direction, the use of atomically controlled Pd@Pt quasi-core-shell Cocatalysts in combination with TiO2 as a model semiconductor is described. As demonstrated experimentally, the electron trapping necessary for charge separation is substantially promoted by combining a Schottky junction with interfacial charge polarization, enabled by the three-atom-thick Pt shell. Meanwhile, the increase in electron density and lattice strain would significantly enhance the adsorption of H2O onto Pt surface. Taken together, the improved charge separation and molecular activation dramatically boost the overall efficiency of photocatalytic water splitting.
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Boosting Photocatalytic Water Splitting: Interfacial Charge Polarization in Atomically Controlled Core–Shell Cocatalysts
Angewandte Chemie, 2015Co-Authors: Li Yang, Junling Lu, Jun Jiang, Chunlei Wang, Yujie XiongAbstract:Platinum is a commonly used cocatalyst for improved charge separation and surface reactions in photocatalytic water splitting. It is envisioned that its practical applications can be facilitated by further reducing the material cost and improving the efficacy of Pt Cocatalysts. In this direction, the use of atomically controlled Pd@Pt quasi-core–shell Cocatalysts in combination with TiO2 as a model semiconductor is described. As demonstrated experimentally, the electron trapping necessary for charge separation is substantially promoted by combining a Schottky junction with interfacial charge polarization, enabled by the three-atom-thick Pt shell. Meanwhile, the increase in electron density and lattice strain would significantly enhance the adsorption of H2O onto Pt surface. Taken together, the improved charge separation and molecular activation dramatically boost the overall efficiency of photocatalytic water splitting.