一步法合成高效三元Z型AgBr/Ag/BiVO4光催化剂

Synthesis of efficient ternary AgBr/Ag/BiVO4 Z-scheme photocatalyst by one pot

采用一锅水热法制得三元Z型溴化银(AgBr)/银(Ag)/钒酸铋(BiVO4)即(AgBr/Ag/BiVO4)光催化剂,并对制得的样品的相组成、微观形貌和光催化活性进行了表征。通过可见光照射条件下对罗丹明B的降解来评价AgBr/Ag/BiVO4的光催化活性。结果表明:AgBr/Ag/BiVO4呈圆形或不规则的多面体形状,与纯BiVO4相比,AgBr/Ag/BiVO4复合材料表现出较高的光催化活性,在硝酸银含量为8%,反应温度为90℃,反应时间为12h条件下,制得的AgBr/Ag/BiVO4光催化剂的光催化活性最高,对罗丹明B的降解率达到89.8%。这种增强的光催化活性是由于从纯Ag转移BiVO4可见光下导带电子,然后迅速转移到AgBr的价带,而光生空穴在溴化银价带,抑制光生电子和空穴的复合,导致AgBr/Ag/BiVO4光催化剂具有较好的光催化活性。

An efficient ternary silver bromide(AgBr)/silver(Ag)/bismuth vanadate(BiVO4)(AgBr/Ag/BiVO4)photocatalysts with different amounts of Ag and AgBr were obtained by one pot hydrothermal method.The phase composition,micro-morphology and photocatalytic activity of the as-prepared samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM)and UV-Vis absorption spectra(UV-Vis),respectively.UV-Vis was used to assess its degradation of rhodamine B(RhB)aqueous solution under visible-light irradiation.It was confirmed that AgBr/Ag/BiVO4 was successfully synthesized by XRD,and the photocatalysts was round or irregular polyhedron shape by SEM.Compared with the pure BiVO4,AgBr/Ag/BiVO4 exhibited higher photocatalytic activity.The results indicated that the AgBr/Ag/BiVO4(8%)showed the highest RhB degradation rate,reaching up to 89.8%.Such enchanced photocatalytic activity was due to the fact that electron from the conduction band of BiVO4 transferred to pure Ag under visible light,then quickly transferred to the valence band of AgBr,whereas photogenerated holes in the valence band of AgBr.This inhibited the recombination of photogenerated electrons and holes.