Boosting electrocatalytic hydrogen evolution over the wide pH range for CoP3 nanowire arrays via Ni doping

Abstract

CoP 3 is a promising electrocatalyst for the hydrogen evolution reaction, however it is still challenging for CoP 3 -based catalyst to deliver excellent activities in a wide pH range. In this work, the self-standing Ni-doped CoP 3 nanowire arrays (Ni-CoP 3 NWs) on carbon fiber paper were synthesized by hydrothermal method followed with an in situ phosphating process. The results show that the Ni doping effectively boosts the electrocatalytic hydrogen evolution for CoP 3 NWs over the wide pH range with good stability. The Ni doped CoP 3 NWs sample with the Ni: Co mole ratio of 10% (Ni-CoP 3 -10%) shows a low overpotential of 66 mV to afford the current density of 10 mA cm −2 in 0.5 M H 2 SO 4 , which is the optimal catalytic performance in this work. Furthermore, Ni-CoP 3 -10% sample also shows excellent electrocatalytic performance in alkaline and neutral conditions, which needs the overpotential of 114 and 131 mV to afford the current density of 10 mA cm −2 in 1 M KOH and 1 M PBS, respectively. The enhanced electrocatalytic activity can be ascribed to that the Ni doping improves the electron transport, increases the electrochemical active surface area and optimizes the Gibbs free energy of hydrogen adsorption for the CoP 3 NWs, which develops it as a promising electrochemical catalyst for hydrogen evolution. • Ni doped CoP 3 nanowire arrays are prepared by vacuum encapsulation technique. • Ni doping boosts the HER activity for CoP 3 in wide pH media. • The reasons of the enhanced HER performance for Ni doped CoP 3 is revealed.