Atomic ruthenium modification of nickel-cobalt alloy for enhanced alkaline hydrogen evolution

Density functional theory (DFT) is used to predict the behavior of ruthenium-doped nickel cobalt alloy in the alkaline hydrogen evolution reaction (HER). According to DFT calculation, a synergistic effect at the Ru-Ni/Co interface is generated to accelerate water dissociation and optimize the adsorption-desorption energetics toward the H intermediate. However, excessive Ru introduction will lead to over-strong hydrogen adsorption on the catalyst surface, thus limiting H2 release. As a proof of concept, we design a series of NiCoRux/SP, among which the optimized NiCoRu0.2/SP electrocatalyst achieves an overpotential of 59 mV at 10 mA cm−2, while excessive Ru incorporation (NiCoRu0.3/SP) diminishes the HER activity. X-ray absorption spectroscopy and other characterizations further confirm that the interface-induced electron transfer from atomic Ru to its surrounding Ni/Co, and the activity degradation caused by excessive Ru incorporation is attributed to the generation of Ru cluster that sacrifices the interface between Ru atom and Ni/Co.