Nanostructures Ni2P / MoP @ N – doping porous carbon for efficient hydrogen evolution over a broad pH range

Abstract

Given its clean energy and absence of exhaust gases, hydrogen is an ideal candidate for energy demand. Electrochemical hydrogen evolution reaction (HER) have attracted increasing attention, and non-precious metal compounds have been considered as next-generation catalysts to replace the traditional Pt-based catalysts in this reaction. This study adopts a novel sol-gel method of chitosan and formaldehyde to prepare an N-doped carbon matrix with Nickel phosphide (Ni2P) and Molybdenum phosphide (MoP) loading. Phytic acid is used as the P source to dissolve chitosan. The interface between Ni2P and MoP in the as-prepared catalysts facilitates HER with an excellent stability in a wide pH universal solution. The onset potentials of the catalyst are 300, 200, and 5 mV in 0.5 mol L−1 sulfuric acid, 1.0 mol L−1 phosphate buffer solution, and 1.0 mol L−1 potassium hydroxide, respectively, and the corresponding Tafel slopes are 63, 99, and 64 mV dec−1. Density functional theory is adopted to support the experiment. Results suggest that the synergistic effect from the interface can obviously reduce the hydrogen adsorption free energy to benefit the adsorption/desorption.