Ameliorating the electronic environment of NiCoP by halogen doping: A strategy for boosting hydrogen evolution performance

Abstract

The design of highly efficient and robust non-noble metal water splitting catalysts for hydrogen production is crucial to reduce overpotential and energy consumption. Herein, a strategy for in-situ growth of halogen-doped NiCoP (X-NiCoP/NF, X = F, Cl, and Br) catalysts with special morphology on nickel foam is proposed. Both the experimental results and theoretical calculations reveal that the downshift of the d-band center energy can regulate the charge distribution of NiCoP owing to doping of strong electronegativity halogen, thus optimizing the Gibbs free energy of H* absorption (△GH*). The F-NiCoP/NF catalyst achieves remarkable HER activity under alkaline conditions, with overpotential at 10 mA cm−2 (η10) of 59 mV and Tafel slope of 48.9 mV dec−1 in 1.0 M KOH. Moreover, F-doping significantly increases the electrochemically active surface area (ECSA) and turnover frequency (TOF), suggestive of the F promotes the formation of highly dispersed high intrinsic active sites. The F-NiCoP/NF exhibits excellent stability with a negligible decrease in activity after durability tests. This work sheds light on the facile synthesis of highly active and stable catalysts with strong electronegative atom doping for HER.