Construction of 3D hierarchical microarchitectures of Z-scheme UiO-66-(COOH)2/ZnIn2S4 hybrid decorated with non-noble MoS2 cocatalyst: A highly efficient photocatalyst for hydrogen evolution and Cr(VI) reduction

Abstract

To solve the problem of energy shortage and environmental pollution, the construction of properly designed photocatalysts is a promising method. Here, UiO-66-(COOH)2/ZnIn2S4 Z-scheme photocatalyst decorated with MoS2 nanosheets was designed and constructed as a novel 3D hierarchical structure via hydrothermal methods. In this particular 3D hierarchical structure, the UiO-66-(COOH)2 nanoparticles are decorated in the interweaving petal nanosheets of ZnIn2S4 microspheres, while the co-catalyst of MoS2 is folded at the edge of these interweaving petals. The excellent heterojunctions with highly exposed catalytic active sites are correspondingly built, and the close interfacial interaction between UiO-66-(COOH)2, MoS2 and ZnIn2S4 create a stage for fast transfer of photogenerated electrons, which are both effective for the photocatalytic reaction process. Also, the Z-scheme charge-transfer process improves the oxidizability and reducibility between UiO-66-(COOH)2 and ZnIn2S4. As a result, the optimized UiO-66-(COOH)2/MoS2/ZnIn2S4 photocatalyst exhibits excellent photocatalytic hydrogen production (18.794 mmol h−1 g−1) and reduction of Cr(VI) (0.06850 min−1) under simulated solar light irradiation, which are 15.3 and 6.7 times higher than that of bare ZnIn2S4, respectively, and also the prominent stability and excellent recyclability are obtained. This study provides new insights into the research on the Z-scheme system containing MOF components for growing energy and environmental demands.