Seawater splitting for high-efficiency hydrogen evolution by alloyed PtNi x electrocatalysts

Robust electrocatalyst is a prerequisite to realize high-efficiency hydrogen evolution by water splitting. Expensive platinum (Pt) is a preferred electrode catalyst for state-of-the-art hydrogen evolution reaction (HER). We present here a category of alloyed PtNix electrocatalysts by a facile green chemical reduction method, which are used to catalyze HER during seawater splitting. The catalytic performances are optimized by tuning stoichiometric Pt/Ni ratio, yielding a maximized catalytic behavior for PtNi5 electrode. The minimized onset potential is as low as −0.38 V and the corresponding Tafel slope is 119 mV dec−1. Moreover, the launched alloy electrodes have remarkable stability at −1.2 V over 12 h. The high efficiency as well as good durability demonstrates the PtNix electrocatalysts to be promising in practical applications.