Bridging the gap between metallic MoO2 and ZnIn2S4 for enhanced photocatalytic H2 production

Abstract

Noble metal-free cocatalysts have shown unprecedented potential in enhancing photocatalytic H2 evolution. However, it remains challenging to accelerate the carrier transfer rate by circuiting the substantial Schottky barrier between the metallic cocatalyst and the semiconductor. Herein, an in-situ carbonization strategy is used to accurately anchor MoO2 nanoparticles onto the surface of conductive carbon rods (MoO2/C), which serves as an efficient and stable metallic cocatalyst for ZnIn2S4 towards photocatalytic H2 evolution. The in-site derived carbon skeleton not only prevents the agglomeration of MoO2 nanoparticles thus enriching the active sites for H2 evolution, but also acts as conductor of photogenerated electrons to accelerate electron transfer. In addition, the formed Mo-S bonds at the interface provide additional electron transport channels for hierarchical core–shell MoO2/C@ZnIn2S4 (MO/C@ZIS) heterojunction. It is worth noting that the H2 evolution activity of the optimized MO/C@ZIS sample (2357 μmol·h−1·g−1) is 8.7 times higher than pure ZnIn2S4 (271 μmol·h−1·g−1), and also surpasses the activity of optimized Pt-modified ZnIn2S4 (2123 μmol·h−1·g−1). This work casts a new paradigm for the rational engineering of heterointerface between metallic cocatalysts and semiconductors towards fast electron transport and enhanced photocatalytic performance.