Exploring low-cost and highly active photocatalysts is very urgent to accomplish complete removal of phenolic contaminants and overcome the limitations of the existing photocatalysts.In this study,we designed and synt...Exploring low-cost and highly active photocatalysts is very urgent to accomplish complete removal of phenolic contaminants and overcome the limitations of the existing photocatalysts.In this study,we designed and synthesized noble metal-free TiO2 photocatalysts by introducing bismuth nanoparticles as modifiers of a TiO2 single crystal(Bi-SCTiO2).The Bi-SCTiO2 can make full use of the synergistic effect of a small band overlap and low charge carrier density(Bi)with a high conductivity(single crystal),significantly boosting the separation and migration of the photogenerated charge pairs.Therefore,the Bi-SCTiO2 photocatalyst exhibits a significantly enhanced degradation rate(12 times faster)of 4-nitrophenol than a TiO2 single crystal under simulated sunlight irradiation.Notably,the complete removal of phenolic contaminants is achieved in various water matrices,which not only successfully overcomes the incomplete degradation in many reported photocatalytic systems,but also manifests a significant practical potential for sewage disposal.Therefore,this work presents a new insight in designing and constructing noble metal-free decorated semiconductor single-crystal photocatalysts with excellent activity and cyclability.展开更多
Microstructures and phase compositions of as-cast and extruded ZK60-xBi(x=0-1.64)alloys were investigated.Meanwhile,the tensile mechanical property and hardness were tested.With increasing the Bi content,the as-cast m...Microstructures and phase compositions of as-cast and extruded ZK60-xBi(x=0-1.64)alloys were investigated.Meanwhile,the tensile mechanical property and hardness were tested.With increasing the Bi content,the as-cast microstructure is first refined obviously,and then becomes coarse slightly.New small block compound which is rich in Zr,Zn,Bi and poor in Mg increases gradually,and MgZn_(2) phase decreases gradually.The second phase mainly precipitates along the grain boundary.The as-cast tensile mechanical property is first enhanced obviously,where the tensile strengthσb,yield strengthσ0.2 and elongationδcan reach 265 MPa,151 MPa and 13.5%for ZK60-0.23Bi alloy,respectively,then remains the high value for ZK60-(0.37-1.09)Bi alloys,and finally decreases obviously for ZK60-1.64Bi alloy.After hot extrusion,the obvious dynamic recrystallization occurs.Broken block compound distributes along the extrusion direction by zonal shape.The average grain size can reach only 4-6μm.The extruded tensile mechanical property is enhanced significantly,where σ_(b),σ_(0.2) and δ are at the range of 345-360 MPa,285-300 MPa and 15.5-19.5%,respectively.Extruded tensile fracture exhibits a typical character of ductile fracture.展开更多
文摘Exploring low-cost and highly active photocatalysts is very urgent to accomplish complete removal of phenolic contaminants and overcome the limitations of the existing photocatalysts.In this study,we designed and synthesized noble metal-free TiO2 photocatalysts by introducing bismuth nanoparticles as modifiers of a TiO2 single crystal(Bi-SCTiO2).The Bi-SCTiO2 can make full use of the synergistic effect of a small band overlap and low charge carrier density(Bi)with a high conductivity(single crystal),significantly boosting the separation and migration of the photogenerated charge pairs.Therefore,the Bi-SCTiO2 photocatalyst exhibits a significantly enhanced degradation rate(12 times faster)of 4-nitrophenol than a TiO2 single crystal under simulated sunlight irradiation.Notably,the complete removal of phenolic contaminants is achieved in various water matrices,which not only successfully overcomes the incomplete degradation in many reported photocatalytic systems,but also manifests a significant practical potential for sewage disposal.Therefore,this work presents a new insight in designing and constructing noble metal-free decorated semiconductor single-crystal photocatalysts with excellent activity and cyclability.
基金The authors would like to acknowledge theMajor Science and Technology Project of Guangdong Province,China(Grant No.2010A090200078 and 2011A080403008)for financial supports。
文摘Microstructures and phase compositions of as-cast and extruded ZK60-xBi(x=0-1.64)alloys were investigated.Meanwhile,the tensile mechanical property and hardness were tested.With increasing the Bi content,the as-cast microstructure is first refined obviously,and then becomes coarse slightly.New small block compound which is rich in Zr,Zn,Bi and poor in Mg increases gradually,and MgZn_(2) phase decreases gradually.The second phase mainly precipitates along the grain boundary.The as-cast tensile mechanical property is first enhanced obviously,where the tensile strengthσb,yield strengthσ0.2 and elongationδcan reach 265 MPa,151 MPa and 13.5%for ZK60-0.23Bi alloy,respectively,then remains the high value for ZK60-(0.37-1.09)Bi alloys,and finally decreases obviously for ZK60-1.64Bi alloy.After hot extrusion,the obvious dynamic recrystallization occurs.Broken block compound distributes along the extrusion direction by zonal shape.The average grain size can reach only 4-6μm.The extruded tensile mechanical property is enhanced significantly,where σ_(b),σ_(0.2) and δ are at the range of 345-360 MPa,285-300 MPa and 15.5-19.5%,respectively.Extruded tensile fracture exhibits a typical character of ductile fracture.
