Optimizing electronic structure of porous Ni/MoO heterostructure to boost alkaline hydrogen evolution reaction.

Heterostructure engineering is an efficient strategy to synergisticallyimprove electrocatalytic activity. In this work, Ni/MoO heterojunction nanorods with porous structure self-supported on nickel foam (NF) are elaborately designed through a facile solution-evaporationmethod followed by a thermal reduction process. Prominently, the optimal electrocatalyst Ni/MoO@NF-E delivers an exceptionally low overpotential of 19 mV at the current density of 10 mA cm and a small Tafel slope of 52.3 mV dec toward the hydrogen evolution reaction (HER) in alkaline solution. Concurrently, Ni/MoO@NF-E also maintains excellent stability after 120 h of electrolysis or 5000 cyclic voltammetry cycles. The experimental and density functional theory (DFT) results indicate that the enhanced HER performance of Ni/MoO@NF-E should be ascribed to the porous structure in the Ni/MoO nanorods providing more active catalytic site, the moderate Gibbs free energy of hydrogen adsorption (ΔG), as well as strong synergistic effect between Ni and MoO. This work provides an efficient route for developing HER electrocatalysts in alkaline media.