Graphitic C3N4 Decorated with CoP Co‐catalyst: Enhanced and Stable Photocatalytic H2 Evolution Activity from Water under Visible‐light Irradiation

Abstract In this work, graphitic C3N4 decorated with a CoP co‐catalyst (g‐C3N4/CoP) is reported for photocatalytic H2 evolution reaction based on two‐step hydrothermal and phosphidation method. The structure of g‐C3N4/CoP is well confirmed by XRD, FTIR, TEM, XPS, and UV/Vis diffuse reflection spectra techniques. When the weight percentage of CoP loading is 3.4 wt % (g‐C3N4/CoP‐3.4 %), the highest H2 evolution amount of 8.4×102 μmol g−1 is obtained, which is 1.1×103 times than that over pure g‐C3N4. This value also is comparable with that of g‐C3N4 loaded by the same amount of Pt. In cycling experiments, g‐C3N4/CoP‐3.4 % shows a stable photocatalytic activity. In addition, g‐C3N4/CoP‐3.4 % is an efficient photocatalyst for H2 evolution under irradiation with natural solar light. Based on comparative photoluminescence emission spectra, photoelectrochemical I–t curves, EIS Nyquist plots, and polarization curves between g‐C3N4/CoP‐3.4 % and pure g‐C3N4, it is concluded that the presence of the CoP co‐catalyst accelerates the separation and transfer of photogenerated electrons of g‐C3N4, thus resulting in improved photocatalytic activity in the H2 evolution reaction.