When a proton reduction cocatalyst is loaded on an n-type semiconductor for photocatalytic overall water splitting(POWS),the location of water oxidation sites is generally considered at the surface of the semiconducto...When a proton reduction cocatalyst is loaded on an n-type semiconductor for photocatalytic overall water splitting(POWS),the location of water oxidation sites is generally considered at the surface of the semiconductor due to upward band-bending of n-type semiconductor which may ease the transfer of the photogenerated holes to the surface.However,this is not the case for Pt/SrTiO_(3),a model semiconductor based photocatalyst for POWS.It was found that the photogenerated holes are more readily accumulated at the interface between Pt cocatalyst and SrTiO_(3) photocatalyst as probed by photo-oxidative deposition of PbO_(2),indicating that the water oxidation sites are located at the interface between Pt and SrTiO_(3).Electron paramagnetic resonance and scanning transmission electron microscope studies suggest that the interfacial oxygen atoms between Pt and SrTiO_(3) in Pt/SrTiO_(3) after POWS are more readily lost to form oxygen vacancies upon vacuum heat treatment,regardless of Pt loading by photodeposition or impregnation methods,which may serve as additional support for the location of the active sites for water oxidation at the interface.Density functional theory calculations also suggest that the oxygen evolution reaction more readily occurs at the interfacial sites with the lowest overpotential.These experimental and theoretical studies reveal that the more active sites for water oxidation are located at the interface between Pt and SrTiO_(3),rather than on the surface of SrTiO_(3).Hence,the tailor design and control of the interfacial properties are extremely important for the achievement or improvement of the POWS on cocatalyst loaded semiconductor photocatalyst.展开更多
Gold catalysis had been considered a highly efficient candidate for heterogeneous catalysis.It is well established that reducible-material-supported Au NPs are more reactive than the unreducible materials,unless speci...Gold catalysis had been considered a highly efficient candidate for heterogeneous catalysis.It is well established that reducible-material-supported Au NPs are more reactive than the unreducible materials,unless specific modifications are carried out.However,unreducible materials such as carbon materials,silica,and alumina have particular advantages,including the easily controlled surface property,adjustable microscopic structure,earth-abundant reserves,and facile industrial manufacture.New strategies,influences,and mechanisms of modification to enhance the catalytic performance and thermal stability of unreducible-material-supported gold catalysts are among the most attractive research topics in gold catalysis.However,to the best of our knowledge,reports and reviews focused on unreducible-material-supported gold catalysts are lacking.Herein,the above concept will be thoroughly discussed regarding several typical unreducible supports,including the commonly used silica,alumina,carbon materials,and hydroxyapatite.The currently prevailing modification strategies will be summarized in detail from the aspects of theoretical conceptualization and practical methodology,including the ingenious synthesis method for catalyst with a specific structure,the currently prosperous electrostatic adsorption,colloid immobilization,and the applicative thermal gaseous treatment.The influences of physical and chemical modifications on the surface chemistry,electronic structure,interaction/synergy between Au-support/promoter,catalyst morphology and water precipitation will be also summarized.It is assumed that the review will shed light on significant studies on unreducible support in gold catalysis with the purpose of catalytic promotion and the promotion of the potential industrial demands in advance.Furthermore,the review will provide new insights into unreducible supports that can be potentially applied in gold catalysis.展开更多
文摘When a proton reduction cocatalyst is loaded on an n-type semiconductor for photocatalytic overall water splitting(POWS),the location of water oxidation sites is generally considered at the surface of the semiconductor due to upward band-bending of n-type semiconductor which may ease the transfer of the photogenerated holes to the surface.However,this is not the case for Pt/SrTiO_(3),a model semiconductor based photocatalyst for POWS.It was found that the photogenerated holes are more readily accumulated at the interface between Pt cocatalyst and SrTiO_(3) photocatalyst as probed by photo-oxidative deposition of PbO_(2),indicating that the water oxidation sites are located at the interface between Pt and SrTiO_(3).Electron paramagnetic resonance and scanning transmission electron microscope studies suggest that the interfacial oxygen atoms between Pt and SrTiO_(3) in Pt/SrTiO_(3) after POWS are more readily lost to form oxygen vacancies upon vacuum heat treatment,regardless of Pt loading by photodeposition or impregnation methods,which may serve as additional support for the location of the active sites for water oxidation at the interface.Density functional theory calculations also suggest that the oxygen evolution reaction more readily occurs at the interfacial sites with the lowest overpotential.These experimental and theoretical studies reveal that the more active sites for water oxidation are located at the interface between Pt and SrTiO_(3),rather than on the surface of SrTiO_(3).Hence,the tailor design and control of the interfacial properties are extremely important for the achievement or improvement of the POWS on cocatalyst loaded semiconductor photocatalyst.
文摘Gold catalysis had been considered a highly efficient candidate for heterogeneous catalysis.It is well established that reducible-material-supported Au NPs are more reactive than the unreducible materials,unless specific modifications are carried out.However,unreducible materials such as carbon materials,silica,and alumina have particular advantages,including the easily controlled surface property,adjustable microscopic structure,earth-abundant reserves,and facile industrial manufacture.New strategies,influences,and mechanisms of modification to enhance the catalytic performance and thermal stability of unreducible-material-supported gold catalysts are among the most attractive research topics in gold catalysis.However,to the best of our knowledge,reports and reviews focused on unreducible-material-supported gold catalysts are lacking.Herein,the above concept will be thoroughly discussed regarding several typical unreducible supports,including the commonly used silica,alumina,carbon materials,and hydroxyapatite.The currently prevailing modification strategies will be summarized in detail from the aspects of theoretical conceptualization and practical methodology,including the ingenious synthesis method for catalyst with a specific structure,the currently prosperous electrostatic adsorption,colloid immobilization,and the applicative thermal gaseous treatment.The influences of physical and chemical modifications on the surface chemistry,electronic structure,interaction/synergy between Au-support/promoter,catalyst morphology and water precipitation will be also summarized.It is assumed that the review will shed light on significant studies on unreducible support in gold catalysis with the purpose of catalytic promotion and the promotion of the potential industrial demands in advance.Furthermore,the review will provide new insights into unreducible supports that can be potentially applied in gold catalysis.
