Novel Ni2P-microporous nickel phosphite supported on nitrogen doped graphene composite electrocatalyst for efficient hydrogen evolution reaction.

Transition metal phosphides have been regarded as promising HER electrocatalysts for water splitting, the efficiency mass-transfer mechanism can be promoted through constructing microporous structure. In addition, introducing carbon materials as carriers to form interface interaction is beneficial for increasing electronic conductivity so as to promote the catalytic activity furtherly. In this work, a nitrogen-doped graphene (NGO) supported microporous nickel phosphide-nickel phosphite (Ni2P-Ni11(HPO3)8(OH)6@NGO, Ni2P-MPH@NGO), where Ni2P nanoparticles are uniformly filled in the microporous of Ni11(HPO3)8(OH)6 and then supported on the two-dimension NGO via a simple two-step method, has been studied as a novel efficient electrocatalyst for HER. Compared with carbon nanotube and graphene as carbon-based carriers, the optimized Ni2P-MPH@NGO catalyst shows excellent HER performance with a smaller overpotential, lower Tafel slope, as well as long-term catalytic durability under acid conditions. The results demonstrated that the NGO can enhance the catalytic activity of Ni2P-MPH@NGO efficiently. The results show that the synergistic effect of the microporous structure of MPH and NGO effectively improves the catalytic activity of the Ni2P-MPH@NGO composite catalyst, which provides a promising strategy for the design of a new low-cost and high-efficiency HER electrocatalyst.