Photocatalytic Dinitrogen Reduction with Water on Boron-Doped Carbon Nitride Loaded with Nickel Phosphide Particles

Photocatalytic N 2 reduction with water by sunlight irradiation is a challenging issue toward sustainable energy society, but previously reported photocatalysts had suffered from low stability and low activity. We prepared a boron-doped carbon nitride (BCN) semiconductor powder loaded with nickel phosphide particles (Ni 2 P) as cocatalysts. The Ni 2 P/BCN catalyst, when photoirradiated in pure water by simulated sunlight under N 2 flow, successfully produces NH 3 at room temperature. The B doping leads to a positive shift of the valence band level and enhances water oxidation by the photoformed holes. The Ni 2 P particles efficiently receive the conduction band electrons of BCN, leading to enhanced charge separation of the photoformed hole and electron pairs, and behave as N 2 reduction sites. Simulated sunlight irradiation of the catalyst in water stably generates NH 3 with 0.010% solar-to-chemical conversion efficiency. This noble-metal-free system therefore shows a significant potential for N 2 photofixation.