Dual anions engineering on nickel cobalt-based catalyst for optimal hydrogen evolution electrocatalysis

The hydrogen evolution reaction (HER) is a pivotal process for renewable energy storage devices. Improving the intrinsically catalytic activity of earth-abundant metals based electrocatalysts for HER is still a huge challenge. Herein, we put forward a dual phosphorus/sulfur (P/S) doped nickel-cobalt bimetallic material that was grown on nickel foam (S-n-NiCoPx-NF, n = 1-4, NF stands for nickel foam) through a facile one-step phosphorization/sulfuration reaction. Those catalysts represent a novel kind of electrocatalysts with vastly optimized catalytic activity for HER. The S-2-NiCoPx/NF with optimal P/S ratio achieves unexpectedly highly efficient catalytic activity for HER in alkaline medium. The overpotential at the current density of 50 mA cm(-2) is only 144 mV, which is almost 190 mV less than that of pristine nickel-cobalt bimetallic phosphide catalyst (NiCoPx-NF). In addition, the S-2-NiCoPx/NF also has fast reaction kinetics with the smallest Tafel slope of 66 mV/dec and exhibits high stability for HER. This work experimentally demonstrates the advantages of a dual anion modification strategy on improving catalytic activity. Our method offers a new approach to design highly efficient and low-cost electrocatalysts for energy storage and conversion devices. (C) 2020 Elsevier Inc. All rights reserved.

Automated summary

A dual phosphorus/sulfur doped nickel-cobalt bimetallic material with optimized catalytic activity for the hydrogen evolution reaction (HER) was proposed. The catalyst showed highly efficient catalytic activity, fast reaction kinetics, and high stability in alkaline medium, demonstrating the advantages of a dual anion modification strategy for improving catalytic activity.