Stimulated pH‐Dependence Phosphorus Platinum–Nickel Alloy Cluster as Hydrogen Generation Electrocatalyst in Alkaline Solution

Abstract

Platinum-based catalysts play an outstanding role in alkaline hydrogen evolution reaction (HER) but with sluggish reaction kinetics. Herein, stimulated pH-dependence phosphorus-embedded PtNi nano-alloy clusters (P@PtNi/C) with good alkaline HER catalytic activity are obtained. The overpotential of P@PtNi/C at a current density of 10 mA cm−2 is 26 mV in 1M KOH solution. At the overpotential of 70 mV, the mass activity of P@PtNi/C is 4.62 A mgPt−1, which is 21 times that of commercial 20 wt% Pt/C in terms of the unit mass of Pt. Due to the doping of P elements, the electronic interface is optimized, which enhances the OH− sensitivity and enables more OHad* to be involved in the overall alkaline cathode reaction. Density functional theory calculations suggest that PtNi3P/C can promote the further reduction of OHad* to generate Oad*, which plays an important role in the decomposition of H2O* to form OHad*. A closed-looping H2O reduction process that exhibits the pH-dependent characteristics of alkaline HER is proposed. OH− is appropriately integrated into the alkaline HER catalytic process based on P@PtNi/C catalyst, which provides a feasible consideration for the design of alkaline HER catalyst.