Ternary Os-Ag-Si electrocatalysts for hydrogen evolution are more efficient than Os-Au-Si.

Abstract

Hydrogen is considered as a promising energy source because of its high combustion heat and clean products. Among the various hydrogen evolution methods, electrocatalysis is the most convenient and effective way. However it is still problematic to find low-cost and high-efficiency electrocatalysts. In this work, Os-Ag-Si and Os-Au-Si ternary electrocatalysts were investigated. It is interesting that Os-Ag-Si exhibits higher hydrogen evolution performance than that of Os-Au-Si, even though Ag is a worse HER catalyst than Au. The optimal ternary catalyst Os-Ag-Si with mass ratio of 15:15:70 (Os:Ag:Si) was synthesized by a facile SiH bond reduction method, which shows superior hydrogen evolution reaction performance with a low Tafel slope of 40\u202fmV·dec-1. In addition, the current density of Os-Ag-Si-15 catalyst surpasses that of 20% Pt/C when the overpotential is larger than 160\u202fmV. The introduction of Ag in the Os-Ag-Si ternary catalyst could enhance the electrocatalytic activity, reduce the cost of catalysts, and even be better than Os-Au-Si.