Self-Templating Construction of Porous CoSe2 Nanosheet Arrays as Efficient Bifunctional Electrocatalysts for Overall Water Splitting

Abstract

Developing low-cost, high performance, stable non-noble bifunctional electrocatalysts for overall water splitting is of great importance for future energy supplement. Despite recent advances in the synthesis of transition metal selenide nanostructures, the fabrication of porous nanosheet based binder-free electrode with more active sites remains a major challenge. Herein, the self-templating construction of a porous CoSe2 nanosheet array on carbon cloth (p-CoSe2/CC) has been reported by vapor selenizing the preprepared α-Co(OH)2 nanosheet array precursor. Arising from large active surface area, fast diffusion of generated gas and strong structural stability, the as-obtained p-CoSe2/CC can serve as an efficient bifunctional electrocatalyst for both OER and HER in alkaline electrolyte, with a current density of 10 mA cm–2 at overpotential of 243 mV for OER and 138 mV for HER, respectively. Moreover, when p-CoSe2/CC is assembled as an alkaline electrolyzor, it only needs a cell voltage of 1.62 V at 10 mA cm–...