Bi4Ti3O12 nanosheets loaded with Rh as special cocatalysts enhancing visible-light driven water splitting activity of ZnIn2S4 nanosheets

Cocatalysts generally serve as active sites accelerating carrier separation. However, when the hydrophilicity of photocatalyst itself is poor, the trapped electrons or holes on cocatalysts are difficult to react with reactants quickly. In this work, Bi4Ti3O12 nanosheets with excellent hydrophilicity was prepared and then thermally deposited Rh on their surface (Bi4Ti3O12(Rh)), and finally in-suit grew ZnIn2S4 on the surface of Bi4Ti3O12(Rh). Based on the results of photocatalytic performance and materials characterization, it was found that the Bi4Ti3O12(Rh) in the photocatalytic system could be considered as a special cocatalyst rather than formed heterojunction with the ZnIn2S4. Under visible-light irradiation, the Rh acted as an electron trapping site to conduct photogenerated electrons trapping from ZnIn2S4 to the surface of Bi4Ti3O12. This process not only further accelerated carrier separation, but also facilitated electrons reacting with water due to the excellent hydrophilicity of Bi4Ti3O12(Rh), thereby achieving enhanced photocatalytic H2 production performance in the absence of sacrificial agents.