Hollow\nCore–Shell Structured Ni–Sn@C\nNanoparticles: A Novel Electrocatalyst for the Hydrogen Evolution\nReaction

Abstract

Pt-free\nelectrocatalysts with high activity and low cost are highly\npursued for hydrogen production by electrochemically splitting water.\nNi-based alloy catalysts are potential candidates for the hydrogen\nevolution reaction (HER) and have been studied extensively. Here,\nwe synthesized novel hollow core–shell structure Ni–Sn@C\nnanoparticles (NPs) by sol–gel, chemical vapor deposition,\nand etching processes. The prepared electrocatalysts with porous hollow\ncarbon layers have a high conductivity and large active area, which\nexhibit good electrocatalytic activity toward HER. The Tafel slope\nof ∼35 millivolts per decade measured in acidic solution for\nNi–Sn@C NPs is the smallest one to date for the Ni–Sn\nalloy catalysts, and exceeds those of the most non-noble metal catalysts,\nindicating a possible Volmer–Heyrovsky reaction mechanism.\nThe synthetic method can be extended to prepare other hollow core–shell\nstructure electrocatalysts for low-temperature fuel cells.