Manganese dioxides with different exposed crystal plane supported on g-C3N4 for photocatalytic H2 evolution from water splitting

A series of MnO 2 /g-C 3 N 4 composites with different exposed crystal plane were successfully prepared by different synthesized method. UV–Vis, PL , ESR and electrochemical results suggest that the visible-light absorbance, photoexcited electron-separation efficiency and oxygen defects are greatly dependent on the exposed crystal-faceted MnO 2 supported on g-C 3 N 4 . The experimental results display that the exposed crystal plane of MnO 2 have great influences on the photocatalytic hydrogen evolution performance, and the m-MnOCN composite with exposed (111) crystal plane exhibits superior photocatalytic performance for the release of H 2 under visible light irradiation , followed by the order of b-MnOCN [002]> p-MnOCN [110]. Moreover, Mechanism studies have shown that the possible mechanism of photocatalytic hydrogen evolution reaction is Z-scheme mechanism.