Guigao Liu | Hokkaido University (original) (raw)

Papers by Guigao Liu

Research paper thumbnail of Au@Cu 7 S 4 yolk–shell nanoparticles as a 980 nm laser-driven photothermal agent with a heat conversion efficiency of 63%

Research paper thumbnail of In situ construction of α-Bi 2 O 3 /g-C 3 N 4 /β-Bi 2 O 3 composites and their highly efficient photocatalytic performances

Research paper thumbnail of Engineering coordination polymers for photocatalysis

Research paper thumbnail of Surface-Plasmon-Enhanced Photodriven CO2 Reduction Catalyzed by Metal-Organic-Framework-Derived Iron Nanoparticles Encapsulated by Ultrathin Carbon Layers

Advanced materials (Deerfield Beach, Fla.), Jan 22, 2016

Highly efficient utilization of solar light with an excellent reduction capacity has been achieve... more Highly efficient utilization of solar light with an excellent reduction capacity has been achieved for plasmonic Fe@C nanostructures. By carbon layer coating, the optimized catalyst exhibits enhanced selectivity and stability applied to the solar-driven reduction of CO2 into CO. The surface-plasmon effect of iron particles has been proposed to excite CO2 molecules, and thereby facilitates the final reaction activity.

Research paper thumbnail of Room-temperature driven and visible light enhanced dehydrogenation reactions catalysed by basic Au/SrTiO 3

Research paper thumbnail of A Co3O4-embedded porous ZnO rhombic dodecahedron prepared using zeolitic imidazolate frameworks as precursors for CO2 photoreduction

Nanoscale, Jan 7, 2016

Metal-organic frameworks (MOFs) are attracting considerable attention for their use as both the p... more Metal-organic frameworks (MOFs) are attracting considerable attention for their use as both the precursor and the template to prepare metal oxides or carbon-based materials. For the first time in this paper, the core-shell ZIF-8@ZIF-67 crystals are thermally converted into porous ZnO@Co3O4 composites by combining a seed-mediated growth process with a two-step calcination. The designed porous ZnO@Co3O4 composites exhibited the highest photocatalytic activity with an excellent stability for the reduction of CO2 among the commonly reported composite photocatalysts. Their superior photocatalytic performance is demonstrated to be resulting from the unique porous structure of ZnO@Co3O4 and the co-catalytic function of Co3O4 which can effectively suppress the photocorrosion of ZnO.

Research paper thumbnail of Active Sites Implanted Carbon Cages in Core-Shell Architecture: Highly Active and Durable Electrocatalyst for Hydrogen Evolution Reaction

ACS nano, Jan 9, 2015

Low efficiency and poor stability are two major challenges we encounter in the exploration of non... more Low efficiency and poor stability are two major challenges we encounter in the exploration of non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) in both acidic and alkaline environment. Herein, the hybrid of cobalt encapsulated by N, B codoped ultrathin carbon cages (Co@BCN) is first introduced as a highly active and durable nonprecious metal electrocatalysts for HER, which is constructed by a bottom-up approach using metal organic frameworks (MOFs) as precursor and self-sacrificing template. The optimized catalyst exhibited remarkable electrocatalytic performance for hydrogen production from both both acidic and alkaline media. Stability investigation reveals the overcoating of carbon cages can effectively avoid the corrosion and oxidation of the catalyst under extreme acidic and alkaline environment. Electrochemical active surface area (EASA) evaluation and density functional theory (DFT) calculations revealed that the synergetic effect between the encapsul...

Research paper thumbnail of Crystal-facet-dependent hot-electron transfer in plasmonic-Au/semiconductor heterostructures for efficient solar photocatalysis

J. Mater. Chem. C, 2015

ABSTRACT Here, using Au-BiOCl as models, we show the significant crystal facet effects of semicon... more ABSTRACT Here, using Au-BiOCl as models, we show the significant crystal facet effects of semiconductor on hot-electron transfer within such plasmonic heterostructures under visible-light. It is found that {010} facets of BiOCl are greatly advantageous over {001} facets for the hot-electron injection, as evidenced by steady-state diffuse reflectance spectroscopy and photoelectrochemical measurements. Consequently, Au-BiOCl-010 exhibits a superior activity for photocatalytic aerobic oxidation of 2-propanol with a quantum efficiency of 1.3%, being 3.5 times higher than that of Au-BiOCl-001. The differences in band structure between {001} and {010} facets of BiOCl may account for the facet-dependent hot-electron transfer characteristics.

Research paper thumbnail of Nature-Inspired Environmental "Phosphorylation" Boosts Photocatalytic H2 Production over Carbon Nitride Nanosheets under Visible-Light Irradiation

Angewandte Chemie (International ed. in English), Jan 21, 2015

Inspired by the crucial roles of phosphates in natural photosynthesis, we explored an environment... more Inspired by the crucial roles of phosphates in natural photosynthesis, we explored an environmental "phosphorylation" strategy for boosting photocatalytic H2 production over g-C3 N4 nanosheets under visible light. As expected, a substantial improvement was observed in the rate of H2 evolution to 947 μmol h(-1) , and the apparent quantum yield was as high as 26.1 % at 420 nm. The synergy of enhanced proton reduction and improved hole oxidation is proposed to account for the markedly increased activity. Our findings may provide a promising and facile approach to highly efficient photocatalysis for solar-energy conversion.

Research paper thumbnail of Crystal-Facet-Dependent Hot-Electron Transfer in Plasmonic-Au/Semiconductor Heterostructures for Efficient Solar Photocatalysis

Journal of Materials Chemistry C

Here, using Au-BiOCl as models, we show the significant crystal facet effects of semiconductor on... more Here, using Au-BiOCl as models, we show the significant crystal facet effects of semiconductor on hot-electron transfer within such plasmonic heterostructures under visible-light. It is found that {010} facets of BiOCl are greatly advantageous over {001} facets for the hot-electron injection, as evidenced by steady-state diffuse reflectance spectroscopy and photoelectrochemical measurements. Consequently, Au-BiOCl-010 exhibits a superior activity for photocatalytic aerobic oxidation of 2-propanol with a quantum efficiency of 1.3%, being 3.5 times higher than that of Au-BiOCl-001. The differences in band structure between {001} and {010} facets of BiOCl may account for the facet-dependent hot-electron transfer characteristics.

Research paper thumbnail of Band-structure-controlled BiO(ClBr) (1−x)/2 I x solid solutions for visible-light photocatalysis

J. Mater. Chem. A, 2015

A group of BiO(ClBr) (1Àx)/2 I x solid solutions with a homogeneous layered tetragonal matlockite... more A group of BiO(ClBr) (1Àx)/2 I x solid solutions with a homogeneous layered tetragonal matlockite structure have been explored as novel visible-light-active photocatalysts. By manipulating the composition ratio of halogen elements (I/(Cl + Br)), the band gaps of these Bi-based solid solutions can be continuously modulated in a rather wide range of 2.88 to 1.82 eV. The density functional calculations demonstrate that this continuous band gap narrowing originates from the gradual increase of valence band maximum with increasing ratio of I/(Cl + Br). The photocatalytic evaluations showed these materials possess composition-dependent photoactivities for degrading 2-propanol (IPA) to acetone and CO 2 under visible light (400 < l < 800 nm). Particularly, the highest acetone evolution rate (215.6 mmol h À1 g À1 ) was achieved over BiO(ClBr) 0.21 I 0.58 , which was 16.5, 11.8 and 659.3 times that of BiO(ClBr) 0.5 , BiOI and commercial Bi 2 O 3 , respectively. And BiO(ClBr) 0.375 I 0.25 exhibited the best photocatalytic performance for CO 2 evolution (4.8 mmol h À1 g À1 , 2.3 and 23.2 times that of BiO(ClBr) 0.5 and BiOI, respectively). In addition, a composition-dependent photocatalysis mechanism is proposed in detail and it involves the indirect hole-induced cOH oxidation or direct hole oxidation of IPA molecules in valence bands and simultaneous electron reduction of oxygen to H 2 O 2 in conduction bands. This work not only shows that BiO(ClBr) (1Àx)/2 I x photocatalysts hold great promise for practical applications but also proves that fabricating solid solutions is an effective approach to develop highly efficient visible-light photocatalysts. † Electronic supplementary information (ESI) available: Experimental procedures and additional experimental results including SEM images, band gaps, crystal structures, surface areas, and other data of BiO(ClBr) (1Àx)/2 I x solid solutions. See Proposed mechanism of photooxidizing IPA over BiO-(ClBr) (1Àx)/2 I x solid solutions.

Research paper thumbnail of Exceptional enhancement of H2 production in alkaline environment over plasmonic Au/TiO2 photocatalyst under visible light

APL Materials, 2015

Effects of inorganic electron donors in photocatalytic hydrogen production over Ru/(CuAg)0.15In0.... more Effects of inorganic electron donors in photocatalytic hydrogen production over Ru/(CuAg)0.15In0.3Zn1.4S2 under visible light irradiation

Research paper thumbnail of Nanorod-like α-Bi 2 O 3 : a highly active photocatalyst synthesized using g-C 3 N 4 as a template

Research paper thumbnail of Efficient visible driven photocatalyst, silver phosphate: performance, understanding and perspective

Chemical Society reviews, Jan 23, 2015

Photocatalysis is a promising technology that can contribute to renewable energy production from ... more Photocatalysis is a promising technology that can contribute to renewable energy production from water and water purification. In order to further develop the field and meet industrial requirements, it is imperative to focus on advancing high efficiency visible light photocatalysts, such as silver phosphate (Ag3PO4). This review aims to highlight the recent progress made in the field, focusing on oxygen production from water, and organic contaminant decomposition using Ag3PO4. The most important advances are discussed and explained in detail, including semiconductor-semiconductor junctions, metal-semiconductor junctions, exposing facet control, and fundamental understanding using advanced spectroscopies and computational chemistry. The review then concludes by critically summarising both findings and current perspectives, and ultimately how the field might best advance in the near future.

Research paper thumbnail of Synthesis and photocatalytic properties of metastable β-Bi 2 O 3 stabilized by surface-coordination effects

J. Mater. Chem. A, 2015

A metastable semiconductor, b-Bi 2 O 3 , was successfully synthesized with the precursor Bi 2 O 2... more A metastable semiconductor, b-Bi 2 O 3 , was successfully synthesized with the precursor Bi 2 O 2 CO 3 in this study, which showed much higher photocatalytic activity in the photooxidation of isopropyl alcohol (IPA) than thermally stable a-Bi 2 O 3 . The prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HRTEM). Based on the previous study, a surface CO 3 2À coordination effect was proposed to understand the formation mechanism of b-Bi 2 O 3 at room temperature. This speculation was supported by the surface chemical states' differences between a-and b-Bi 2 O 3 , which were studied using Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and

Research paper thumbnail of Fabrication of Ge quantum dots doped TiO2 films with high optical absorption properties via layer-by-layer ion-beam sputtering

Materials Letters, 2012

Ge quantum dots (QDs)-doped TiO 2 films were prepared by ion-beam sputtering. TEM results showed ... more Ge quantum dots (QDs)-doped TiO 2 films were prepared by ion-beam sputtering. TEM results showed Ge QDs were in a uniform size distribution and high density. XPS indicated that Ge incorporated in the TiO 2 films was in elemental form. The Stranski-Krastanov growth mode was accounted for the growth of Ge QDs in TiO 2 films by AFM analysis. Optical absorption spectra exhibited the optical response of the Ge QDsdoped TiO 2 films was shifted from UV to the near infrared region, suggesting a good optical absorption property.

Research paper thumbnail of In situ synthesis of ordered mesoporous Co-doped TiO2 and their enhanced photocatalytic activities and selectivities in reduction of CO2

Research paper thumbnail of Photoreduction of CO2 over the well-crystallized ordered mesoporous TiO2 with the confined space effect

Nano Energy, 2014

Ordered mesoporous titanium dioxide with crystalline wall was successfully synthesized by combini... more Ordered mesoporous titanium dioxide with crystalline wall was successfully synthesized by combining evaporation induced self-assembly process with two-step calcination processes. The ordered mesoporous titanium dioxide not only shows a higher production efficiency of CH 4 , which is 71 times and 53 times higher than that of commercial titanium dioxide (P25) and disordered mesoporous titanium dioxide, respectively, but also exhibits a better stability for CO 2 photoreduction. The remarkable performance of the ordered mesoporous titanium dioxide for CO 2 photoreduction probably benefits from the confined space effect of ordered mesoporous structure because (1) the active sites exist not only on the surface of the particles, but also exist in the pores; (2) gas molecules collide with the pore walls more frequently in the case of Knudsen diffusion; (3) the highly ordered mesoporous structure develops a high-efficient CO 2 adsorption ability, smooth flow of gas molecules and improved separation and transport of electron-hole.

Research paper thumbnail of Efficient organic degradation under visible light by α-Bi2O3 with a CuOx-assistant electron transfer process

Applied Catalysis B: Environmental, 2015

In this study, we have found that CuO x modified ␣-Bi 2 O 3 is an excellent photocatalytic materi... more In this study, we have found that CuO x modified ␣-Bi 2 O 3 is an excellent photocatalytic material for the visible-light-driven degradation of various organic compounds including RhB, MO, 2,4-DCP, and gaseous IPA. A detailed study on the mechanism of the photocatalytic reaction was performed by measuring the photogenerated • OH and H 2 O 2 under visible light irradiation. The results indicate that modifying CuO x on the surface of ␣-Bi 2 O 3 significantly promotes the separation of the photogenerated electrons and holes of ␣-Bi 2 O 3 . The important role of CuO x was further investigated by detecting the valence states change of Cu before and after the photocatalysis, using ESR and XPS. It was found that, the Cu states within the CuO x clusters are the coexistence of Cu(II) clusters, CuO and Cu. As a result, the enhancement of photocatalytic activity by CuO x modification can be attributed to a CuO x -assistant electron transfer process (CuO x -AETP), which involves in two electron excitation paths and a Cu cycle of different valence states.

Research paper thumbnail of A highly durable p-LaFeO3/n-Fe2O3 photocell for effective water splitting under visible light

Chemical communications (Cambridge, England), Jan 2, 2015

A new p-type photocathode LaFeO 3 was successfully fabricated, and a stable (120 h) and effective... more A new p-type photocathode LaFeO 3 was successfully fabricated, and a stable (120 h) and effective water splitting (H 2 : 11.5 lmol h À1 , O 2 : 5.7 lmol h À1 ) was realized via construction of a p-LaFeO 3 / n-Fe 2 O 3 photocell. This study offers a new alternative to p-type photocathode materials and the low cost design of durable PEC devices for solar conversion.

Research paper thumbnail of Au@Cu 7 S 4 yolk–shell nanoparticles as a 980 nm laser-driven photothermal agent with a heat conversion efficiency of 63%

Research paper thumbnail of In situ construction of α-Bi 2 O 3 /g-C 3 N 4 /β-Bi 2 O 3 composites and their highly efficient photocatalytic performances

Research paper thumbnail of Engineering coordination polymers for photocatalysis

Research paper thumbnail of Surface-Plasmon-Enhanced Photodriven CO2 Reduction Catalyzed by Metal-Organic-Framework-Derived Iron Nanoparticles Encapsulated by Ultrathin Carbon Layers

Advanced materials (Deerfield Beach, Fla.), Jan 22, 2016

Highly efficient utilization of solar light with an excellent reduction capacity has been achieve... more Highly efficient utilization of solar light with an excellent reduction capacity has been achieved for plasmonic Fe@C nanostructures. By carbon layer coating, the optimized catalyst exhibits enhanced selectivity and stability applied to the solar-driven reduction of CO2 into CO. The surface-plasmon effect of iron particles has been proposed to excite CO2 molecules, and thereby facilitates the final reaction activity.

Research paper thumbnail of Room-temperature driven and visible light enhanced dehydrogenation reactions catalysed by basic Au/SrTiO 3

Research paper thumbnail of A Co3O4-embedded porous ZnO rhombic dodecahedron prepared using zeolitic imidazolate frameworks as precursors for CO2 photoreduction

Nanoscale, Jan 7, 2016

Metal-organic frameworks (MOFs) are attracting considerable attention for their use as both the p... more Metal-organic frameworks (MOFs) are attracting considerable attention for their use as both the precursor and the template to prepare metal oxides or carbon-based materials. For the first time in this paper, the core-shell ZIF-8@ZIF-67 crystals are thermally converted into porous ZnO@Co3O4 composites by combining a seed-mediated growth process with a two-step calcination. The designed porous ZnO@Co3O4 composites exhibited the highest photocatalytic activity with an excellent stability for the reduction of CO2 among the commonly reported composite photocatalysts. Their superior photocatalytic performance is demonstrated to be resulting from the unique porous structure of ZnO@Co3O4 and the co-catalytic function of Co3O4 which can effectively suppress the photocorrosion of ZnO.

Research paper thumbnail of Active Sites Implanted Carbon Cages in Core-Shell Architecture: Highly Active and Durable Electrocatalyst for Hydrogen Evolution Reaction

ACS nano, Jan 9, 2015

Low efficiency and poor stability are two major challenges we encounter in the exploration of non... more Low efficiency and poor stability are two major challenges we encounter in the exploration of non-noble metal electrocatalysts for the hydrogen evolution reaction (HER) in both acidic and alkaline environment. Herein, the hybrid of cobalt encapsulated by N, B codoped ultrathin carbon cages (Co@BCN) is first introduced as a highly active and durable nonprecious metal electrocatalysts for HER, which is constructed by a bottom-up approach using metal organic frameworks (MOFs) as precursor and self-sacrificing template. The optimized catalyst exhibited remarkable electrocatalytic performance for hydrogen production from both both acidic and alkaline media. Stability investigation reveals the overcoating of carbon cages can effectively avoid the corrosion and oxidation of the catalyst under extreme acidic and alkaline environment. Electrochemical active surface area (EASA) evaluation and density functional theory (DFT) calculations revealed that the synergetic effect between the encapsul...

Research paper thumbnail of Crystal-facet-dependent hot-electron transfer in plasmonic-Au/semiconductor heterostructures for efficient solar photocatalysis

J. Mater. Chem. C, 2015

ABSTRACT Here, using Au-BiOCl as models, we show the significant crystal facet effects of semicon... more ABSTRACT Here, using Au-BiOCl as models, we show the significant crystal facet effects of semiconductor on hot-electron transfer within such plasmonic heterostructures under visible-light. It is found that {010} facets of BiOCl are greatly advantageous over {001} facets for the hot-electron injection, as evidenced by steady-state diffuse reflectance spectroscopy and photoelectrochemical measurements. Consequently, Au-BiOCl-010 exhibits a superior activity for photocatalytic aerobic oxidation of 2-propanol with a quantum efficiency of 1.3%, being 3.5 times higher than that of Au-BiOCl-001. The differences in band structure between {001} and {010} facets of BiOCl may account for the facet-dependent hot-electron transfer characteristics.

Research paper thumbnail of Nature-Inspired Environmental "Phosphorylation" Boosts Photocatalytic H2 Production over Carbon Nitride Nanosheets under Visible-Light Irradiation

Angewandte Chemie (International ed. in English), Jan 21, 2015

Inspired by the crucial roles of phosphates in natural photosynthesis, we explored an environment... more Inspired by the crucial roles of phosphates in natural photosynthesis, we explored an environmental "phosphorylation" strategy for boosting photocatalytic H2 production over g-C3 N4 nanosheets under visible light. As expected, a substantial improvement was observed in the rate of H2 evolution to 947 μmol h(-1) , and the apparent quantum yield was as high as 26.1 % at 420 nm. The synergy of enhanced proton reduction and improved hole oxidation is proposed to account for the markedly increased activity. Our findings may provide a promising and facile approach to highly efficient photocatalysis for solar-energy conversion.

Research paper thumbnail of Crystal-Facet-Dependent Hot-Electron Transfer in Plasmonic-Au/Semiconductor Heterostructures for Efficient Solar Photocatalysis

Journal of Materials Chemistry C

Here, using Au-BiOCl as models, we show the significant crystal facet effects of semiconductor on... more Here, using Au-BiOCl as models, we show the significant crystal facet effects of semiconductor on hot-electron transfer within such plasmonic heterostructures under visible-light. It is found that {010} facets of BiOCl are greatly advantageous over {001} facets for the hot-electron injection, as evidenced by steady-state diffuse reflectance spectroscopy and photoelectrochemical measurements. Consequently, Au-BiOCl-010 exhibits a superior activity for photocatalytic aerobic oxidation of 2-propanol with a quantum efficiency of 1.3%, being 3.5 times higher than that of Au-BiOCl-001. The differences in band structure between {001} and {010} facets of BiOCl may account for the facet-dependent hot-electron transfer characteristics.

Research paper thumbnail of Band-structure-controlled BiO(ClBr) (1−x)/2 I x solid solutions for visible-light photocatalysis

J. Mater. Chem. A, 2015

A group of BiO(ClBr) (1Àx)/2 I x solid solutions with a homogeneous layered tetragonal matlockite... more A group of BiO(ClBr) (1Àx)/2 I x solid solutions with a homogeneous layered tetragonal matlockite structure have been explored as novel visible-light-active photocatalysts. By manipulating the composition ratio of halogen elements (I/(Cl + Br)), the band gaps of these Bi-based solid solutions can be continuously modulated in a rather wide range of 2.88 to 1.82 eV. The density functional calculations demonstrate that this continuous band gap narrowing originates from the gradual increase of valence band maximum with increasing ratio of I/(Cl + Br). The photocatalytic evaluations showed these materials possess composition-dependent photoactivities for degrading 2-propanol (IPA) to acetone and CO 2 under visible light (400 < l < 800 nm). Particularly, the highest acetone evolution rate (215.6 mmol h À1 g À1 ) was achieved over BiO(ClBr) 0.21 I 0.58 , which was 16.5, 11.8 and 659.3 times that of BiO(ClBr) 0.5 , BiOI and commercial Bi 2 O 3 , respectively. And BiO(ClBr) 0.375 I 0.25 exhibited the best photocatalytic performance for CO 2 evolution (4.8 mmol h À1 g À1 , 2.3 and 23.2 times that of BiO(ClBr) 0.5 and BiOI, respectively). In addition, a composition-dependent photocatalysis mechanism is proposed in detail and it involves the indirect hole-induced cOH oxidation or direct hole oxidation of IPA molecules in valence bands and simultaneous electron reduction of oxygen to H 2 O 2 in conduction bands. This work not only shows that BiO(ClBr) (1Àx)/2 I x photocatalysts hold great promise for practical applications but also proves that fabricating solid solutions is an effective approach to develop highly efficient visible-light photocatalysts. † Electronic supplementary information (ESI) available: Experimental procedures and additional experimental results including SEM images, band gaps, crystal structures, surface areas, and other data of BiO(ClBr) (1Àx)/2 I x solid solutions. See Proposed mechanism of photooxidizing IPA over BiO-(ClBr) (1Àx)/2 I x solid solutions.

Research paper thumbnail of Exceptional enhancement of H2 production in alkaline environment over plasmonic Au/TiO2 photocatalyst under visible light

APL Materials, 2015

Effects of inorganic electron donors in photocatalytic hydrogen production over Ru/(CuAg)0.15In0.... more Effects of inorganic electron donors in photocatalytic hydrogen production over Ru/(CuAg)0.15In0.3Zn1.4S2 under visible light irradiation

Research paper thumbnail of Nanorod-like α-Bi 2 O 3 : a highly active photocatalyst synthesized using g-C 3 N 4 as a template

Research paper thumbnail of Efficient visible driven photocatalyst, silver phosphate: performance, understanding and perspective

Chemical Society reviews, Jan 23, 2015

Photocatalysis is a promising technology that can contribute to renewable energy production from ... more Photocatalysis is a promising technology that can contribute to renewable energy production from water and water purification. In order to further develop the field and meet industrial requirements, it is imperative to focus on advancing high efficiency visible light photocatalysts, such as silver phosphate (Ag3PO4). This review aims to highlight the recent progress made in the field, focusing on oxygen production from water, and organic contaminant decomposition using Ag3PO4. The most important advances are discussed and explained in detail, including semiconductor-semiconductor junctions, metal-semiconductor junctions, exposing facet control, and fundamental understanding using advanced spectroscopies and computational chemistry. The review then concludes by critically summarising both findings and current perspectives, and ultimately how the field might best advance in the near future.

Research paper thumbnail of Synthesis and photocatalytic properties of metastable β-Bi 2 O 3 stabilized by surface-coordination effects

J. Mater. Chem. A, 2015

A metastable semiconductor, b-Bi 2 O 3 , was successfully synthesized with the precursor Bi 2 O 2... more A metastable semiconductor, b-Bi 2 O 3 , was successfully synthesized with the precursor Bi 2 O 2 CO 3 in this study, which showed much higher photocatalytic activity in the photooxidation of isopropyl alcohol (IPA) than thermally stable a-Bi 2 O 3 . The prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HRTEM). Based on the previous study, a surface CO 3 2À coordination effect was proposed to understand the formation mechanism of b-Bi 2 O 3 at room temperature. This speculation was supported by the surface chemical states' differences between a-and b-Bi 2 O 3 , which were studied using Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and

Research paper thumbnail of Fabrication of Ge quantum dots doped TiO2 films with high optical absorption properties via layer-by-layer ion-beam sputtering

Materials Letters, 2012

Ge quantum dots (QDs)-doped TiO 2 films were prepared by ion-beam sputtering. TEM results showed ... more Ge quantum dots (QDs)-doped TiO 2 films were prepared by ion-beam sputtering. TEM results showed Ge QDs were in a uniform size distribution and high density. XPS indicated that Ge incorporated in the TiO 2 films was in elemental form. The Stranski-Krastanov growth mode was accounted for the growth of Ge QDs in TiO 2 films by AFM analysis. Optical absorption spectra exhibited the optical response of the Ge QDsdoped TiO 2 films was shifted from UV to the near infrared region, suggesting a good optical absorption property.

Research paper thumbnail of In situ synthesis of ordered mesoporous Co-doped TiO2 and their enhanced photocatalytic activities and selectivities in reduction of CO2

Research paper thumbnail of Photoreduction of CO2 over the well-crystallized ordered mesoporous TiO2 with the confined space effect

Nano Energy, 2014

Ordered mesoporous titanium dioxide with crystalline wall was successfully synthesized by combini... more Ordered mesoporous titanium dioxide with crystalline wall was successfully synthesized by combining evaporation induced self-assembly process with two-step calcination processes. The ordered mesoporous titanium dioxide not only shows a higher production efficiency of CH 4 , which is 71 times and 53 times higher than that of commercial titanium dioxide (P25) and disordered mesoporous titanium dioxide, respectively, but also exhibits a better stability for CO 2 photoreduction. The remarkable performance of the ordered mesoporous titanium dioxide for CO 2 photoreduction probably benefits from the confined space effect of ordered mesoporous structure because (1) the active sites exist not only on the surface of the particles, but also exist in the pores; (2) gas molecules collide with the pore walls more frequently in the case of Knudsen diffusion; (3) the highly ordered mesoporous structure develops a high-efficient CO 2 adsorption ability, smooth flow of gas molecules and improved separation and transport of electron-hole.

Research paper thumbnail of Efficient organic degradation under visible light by α-Bi2O3 with a CuOx-assistant electron transfer process

Applied Catalysis B: Environmental, 2015

In this study, we have found that CuO x modified ␣-Bi 2 O 3 is an excellent photocatalytic materi... more In this study, we have found that CuO x modified ␣-Bi 2 O 3 is an excellent photocatalytic material for the visible-light-driven degradation of various organic compounds including RhB, MO, 2,4-DCP, and gaseous IPA. A detailed study on the mechanism of the photocatalytic reaction was performed by measuring the photogenerated • OH and H 2 O 2 under visible light irradiation. The results indicate that modifying CuO x on the surface of ␣-Bi 2 O 3 significantly promotes the separation of the photogenerated electrons and holes of ␣-Bi 2 O 3 . The important role of CuO x was further investigated by detecting the valence states change of Cu before and after the photocatalysis, using ESR and XPS. It was found that, the Cu states within the CuO x clusters are the coexistence of Cu(II) clusters, CuO and Cu. As a result, the enhancement of photocatalytic activity by CuO x modification can be attributed to a CuO x -assistant electron transfer process (CuO x -AETP), which involves in two electron excitation paths and a Cu cycle of different valence states.

Research paper thumbnail of A highly durable p-LaFeO3/n-Fe2O3 photocell for effective water splitting under visible light

Chemical communications (Cambridge, England), Jan 2, 2015

A new p-type photocathode LaFeO 3 was successfully fabricated, and a stable (120 h) and effective... more A new p-type photocathode LaFeO 3 was successfully fabricated, and a stable (120 h) and effective water splitting (H 2 : 11.5 lmol h À1 , O 2 : 5.7 lmol h À1 ) was realized via construction of a p-LaFeO 3 / n-Fe 2 O 3 photocell. This study offers a new alternative to p-type photocathode materials and the low cost design of durable PEC devices for solar conversion.