Cobalt-Doped FeSe2-RGO as Highly Active and Stable Electrocatalysts for Hydrogen Evolution Reactions.

Herein, we describe the preparation and testing of Co-doped FeSe2 hybridized with graphene (Fe1-xCoxSe2/RGO), a high-active yet stable electrocatalyst for hydrogen evolution reactions (HERs) in acidic solutions. First, we systematically analyze the composition and morphology of Fe1-xCoxSe2/RGO and attribute its excellent electrochemical performance to its unique architecture-a base of highly conductive graphene with fully exposed active edges that enhances conductivity and facilitates ion/electron transfer. Our experimental measurements indicate elevated HER activity with a moderate overpotential of ∼166 mV at a hydrogen production current density of 10 mA cm(-2), a small Tafel slope of ∼36 mV dec(-1), and long cycling lifespan more than 20 h. The promising results, in addition to the fact that Fe1-xCoxSe2/RGO is a high-performance, precious-metal-free electrocatalyst, pave the way for exciting opportunities in renewable hydrogen production applications.