Unsaturated NiO incorporated PtNi, possessing abundant surface hydroxyl species, as an efficient and durable electrocatalyst for the hydrogen evolution reaction in seawater

Abstract

Creating an abundance of OH* active sites on the surface of an electrocatalyst is an ideal approach for improving both its performance and Cl– corrosion resistance in seawater splitting to generate hydrogen via the hydrogen evolution reactions (HER). However, the development of strategies for designing coordinatively saturated metals that have these sites remains a significant challenge. Herein, we report on the development of NiO/Pt3Ni-300, a coordinatively unsaturated NiO incorporated Pt3Ni, which has the ability to capture large numbers of surface hydroxyl groups during the HER in seawater and, in consequence of this, it exhibits high electrocatalytic activity in seawater. Additionally, benefiting from super-hydrophilicity induced by its rich OH* surface, NiO/Pt3Ni-300 preferentially adsorbs H2O over Cl–. The outstanding HER performance of this catalyst in alkaline seawater is reflected by a low overpotential of 16 mV to drive a current density of 10 mA cm−2, and a 7.7-fold higher turnover frequency compared to that of Pt/C. Moreover, it displays only a small 41 mV drop in overpotential after promotion of the HER for 20 h in alkaline seawater, a value that surpasses those inherent to commercial Pt/C, Pt3Ni, and crystalline NiO incorporated Pt3Ni.