Multi-interfacial Ni/Mo2C ultrafine hybrids anchored on nitrogen-doped carbon nanosheets as a highly efficient electrocatalyst for water splitting

Abstract

Interfacial engineering in the rapid development of high-performance electrocatalysts for water splitting has been explored as a promising strategy to improve catalytic performance due to the tunable free energy of reaction intermediates on the interfacial compositions. Here, multiple-interfacial Ni/molybdenum carbide hybrid nanoparticles embedded in N-doped carbon nanosheets (Ni/Mo2C@NC) electrocatalyst were fabricated via a solid-state co-reduction method. The as-synthesized catalyst exhibits excellent hydrogen evolution reaction (HER) activity with an overpotential of 91 mV at 10 mA/cm2 and a Tafel slope of 74 mV/dec in alkaline solution, and outstanding stability owing to the high conductivity, abundant interfacial active sites, and synergistic effect between Ni and Mo2C nanoparticles. This electrocatalyst as bifunctional electrode possesses an applied voltage of 1.64 V at 10 mA/cm2 and long-term durability in an electrolysis cell. Moreover, density functional theory calculations reveal that the electron transfer across Ni/Mo2C heterointerfaces could optimize the water adsorption/dissociation and H adsorption/desorption capacities, thereby boosting the intrinsic HER activity.