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

In this work, graphitic C3N4 decorated with a CoP co-catalyst (g-C3N4/CoP) is reported for photocatalytic H-2 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 H-2 evolution amount of 8.4 V 10(2) mu molg(-1) is obtained, which is 1.1 V 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 H-2 evolution under irradiation with natural solar light. Based on comparative photoluminescence emission spectra, photoelectrochemical I-t curves, EIS Nyquist plots, and polarization curves between gC(3)N(4)/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 H-2 evolution reaction.