Noble-Metal-Free Iron Phosphide Cocatalyst Loaded Graphitic Carbon Nitride as an Efficient and Robust Photocatalyst for Hydrogen Evolution under Visible Light Irradiation

Photocatalytic hydrogen (H 2 ) evolution from water is a promising and sustainable approach for solar-to chemical energy conversion. However, the development of an efficient, robust, and low-cost visible-light-driven photocatalyst for H 2 evolution is still one of the great challenges. Graphitic carbon nitride (g-C 3 N 4 ) is an attractive candidate, but the activity of pristine g-C 3 N 4 is largely limited. Herein, for the first time, we report the noble-metal-free iron phosphide cocatalyst decorated graphitic carbon nitride (g-C 3 N 4 /Fe x P) as a photocatalyst for the highly efficient and stable H 2 evolution from water splitting irradiated by visible light. The peak H 2 evolution rate of g-C 3 N 4 /Fe x P is ca. 277 times higher than that of pristine g-C 3 N 4 and is almost comparable with the g-C 3 N 4 modified by noble metal Pt cocatalyst. Additionally, g-C 3 N 4 /Fe x P demonstrates almost negligible photocatalytic degradation capability after five repeated cycles. Based on the detail analyses of photoluminescence and surface photovoltage spectra, we find the presence of Fe x P cocatalyst significantly accelerates the separation and transfer of photogenerated electrons of g-C 3 N 4, hence resulting in the high photocatalytic efficiency of g-C 3 N 4 /Fe x P for H 2 production. In addition, the adjacent Fe and P atoms in Fe x P act as dual proton adsorption sites to synergistically facilitate the fast H 2 generation from water.