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, Bi₄Ti₃O₁₂nanosheets with excellent hydrophilicity was prepared and then thermally deposited Rh on their surface (Bi₄Ti₃O₁₂(Rh)), and finally in-suit grew ZnIn₂S₄on 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 ZnIn₂S₄to 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 H₂production performance in the absence of sacrificial agents.