摘要
Defect and charge transfer efficiency of nano-photocatalysts are important factors which influence their photocatalytic performance.In this work,oxygen vacancies are successfully introduced in the synthesis process of Bi_(2)Al_(4)O_(9)/β-Bi_(2)O_(3)heterojunctions through one-step in situ selfcombustion method.High-resolution transmission electron microscopy (HRTEM),UV-Vis diffuse reflectance spectra (UV-Vis DRS),and electron spin resonance (ESR) measurements confirm the existence of oxygen vacancies.In addition,by controlling the ratio of reactants of Bi(NO_(3))_(3)to Al(NO_(3))_(3),the ratio of Bi_(2)Al_(4)O_(9)and β-Bi_(2)O_(3)in the heterojunction can be easily adjusted.Photocurrent responses and surface photovoltage spectroscopy (SPV) indicate that the construction of the Bi_(2)Al_(4)O_(9)/β-Bi_(2)O_(3)heterostructure improves the separation efficiency of the photo-generated electrons and holes.CO_(2)-TPD results imply that the amounts and stability of heterojunctions are enhanced compared with their counterparts.The Bi_(2)Al_(4)O_(9)/β-Bi_(2)O_(3)heterojunction with 14 mol%Bi_(2)Al_(4)O_(9)shows the highest photocatalytic ability for reduction of CO_(2)into CO.The enhanced photoreduction of CO_(2)performance can be ascribed to the synergistic effects of the heterojunction for electron separation and oxygen vacancies for CO_(2)activation.
基金
financial support from the National Natural Science Foundation of China(21776059,21376061)
the Natural Science Foundation for Distinguished Young Scholars of Hebei Province(B2015208010)
the Research Foundation of Hebei Province Education Department(No.ZC2016007)。