Effective construction of semiconductor hetero-nanostructures(HNSs)with a well-defined hetero-interface is of great importance.So far,highly developed liquid-phase chemical routes are often restricted by their heavy u...Effective construction of semiconductor hetero-nanostructures(HNSs)with a well-defined hetero-interface is of great importance.So far,highly developed liquid-phase chemical routes are often restricted by their heavy use of surfactants and/or organic solvents,which inevitably introduce passivated surfaces and interfacial defects in the resultant HNSs.Here,we have developed a novel and efficient in situ epitaxial growth strategy to fabricate HNSs of Ag_(3)PO_(4)quantum dots(QDs)on the external surface of hematite(Fe_(2)O_(3))nanotubes(NTs)(Ag_(3)PO_(4)/Fe_(2)O_(3)NT-HNSs),by intentionally employing chemically adsorbed phosphate anions on the surface of Fe_(2)O_(3)NTs to control the reaction kinetics of phosphate anions and Ag^(+)ions in aqueous solution.In this synthetic strategy,the chemically adsorbed phosphate anions on the surface of the Fe_(2)O_(3)NTs play the dual functions of heterogeneous nucleation and in situ epitaxial growth of Ag_(3)PO_(4)QDs along the direction of(311)on the(113)crystal plane of Fe_(2)O_(3)NTs.That is,they precipitate Ag^(+)ions via gradual dissociation of free phosphate anions and so generate Ag_(3)PO_(4)QDs,and they serve as a bridge and bond for in situ epitaxial growth of Ag_(3)PO_(4)QDs on Fe_(2)O_(3)NTs.Due to the unique coupling of the hetero-interfaces and internal electric field,the as-obtained Ag_(3)PO_(4)/Fe_(2)O_(3)NT-HNSs show efficient separation of photogenerated charge carriers and remarkable enhancement of their reduction and oxidation abilities by a Z-scheme photocatalytic form,significantly improving visible-light photocatalytic activity for decolorization of the organic pollutant rhodamine B.They exhibit a photocatalytic rate constant as large as 3.6×10^(-2) min^(-1),which is two orders of magnitude greater than that of single Fe_(2)O_(3)NTs(9.1×10^(-4) min^(-1)),single Ag_(3)PO_(4)QDs(1.6×10^(-4) min^(-1))as well as the mixture of the two(7.1×10^(-4) min^(-1)),suggesting a highly efficient photocatalyst.The in situ epitaxial growth strategy proposed here constitutes a novel example for fine construction of hetero-nanostructures for solar utilization.展开更多
基金supported by the National Natural Science Foundation of China(21705123,51573144,and 51521001)the Top Talents Lead Cultivation Project of Hubei Province.
文摘Effective construction of semiconductor hetero-nanostructures(HNSs)with a well-defined hetero-interface is of great importance.So far,highly developed liquid-phase chemical routes are often restricted by their heavy use of surfactants and/or organic solvents,which inevitably introduce passivated surfaces and interfacial defects in the resultant HNSs.Here,we have developed a novel and efficient in situ epitaxial growth strategy to fabricate HNSs of Ag_(3)PO_(4)quantum dots(QDs)on the external surface of hematite(Fe_(2)O_(3))nanotubes(NTs)(Ag_(3)PO_(4)/Fe_(2)O_(3)NT-HNSs),by intentionally employing chemically adsorbed phosphate anions on the surface of Fe_(2)O_(3)NTs to control the reaction kinetics of phosphate anions and Ag^(+)ions in aqueous solution.In this synthetic strategy,the chemically adsorbed phosphate anions on the surface of the Fe_(2)O_(3)NTs play the dual functions of heterogeneous nucleation and in situ epitaxial growth of Ag_(3)PO_(4)QDs along the direction of(311)on the(113)crystal plane of Fe_(2)O_(3)NTs.That is,they precipitate Ag^(+)ions via gradual dissociation of free phosphate anions and so generate Ag_(3)PO_(4)QDs,and they serve as a bridge and bond for in situ epitaxial growth of Ag_(3)PO_(4)QDs on Fe_(2)O_(3)NTs.Due to the unique coupling of the hetero-interfaces and internal electric field,the as-obtained Ag_(3)PO_(4)/Fe_(2)O_(3)NT-HNSs show efficient separation of photogenerated charge carriers and remarkable enhancement of their reduction and oxidation abilities by a Z-scheme photocatalytic form,significantly improving visible-light photocatalytic activity for decolorization of the organic pollutant rhodamine B.They exhibit a photocatalytic rate constant as large as 3.6×10^(-2) min^(-1),which is two orders of magnitude greater than that of single Fe_(2)O_(3)NTs(9.1×10^(-4) min^(-1)),single Ag_(3)PO_(4)QDs(1.6×10^(-4) min^(-1))as well as the mixture of the two(7.1×10^(-4) min^(-1)),suggesting a highly efficient photocatalyst.The in situ epitaxial growth strategy proposed here constitutes a novel example for fine construction of hetero-nanostructures for solar utilization.
