Crystal phase engineering boosted photo-electrochemical kinetics of CoSe2 for oxygen evolution catalysis

Abstract

Crystal phase is an important parameter that can determine the electronic structure and catalytic properties of catalysts. In this work, we report the crystal phase dependent photo- and electrocatalytic oxygen evolution reaction (OER) performance of CoSe2. In electrocatalytic reaction, we firstly found that CoSe2 with orthorhombic phase (o-CoSe2) showed a higher OER performance than that of CoSe2 with cubic phase (c-CoSe2). In the further exploration of photocatalytic application using Fe2O3 as light harvester and CoSe2 as cocatalysts, o-CoSe2/Fe2O3 can realize the qualitative changes of photocatalytic oxygen evolution performance from “0″ to “1”. As contrast, c-CoSe2/Fe2O3 cannot work in photocatalytic oxygen evolution process under the same condition. Experimental and theoretical analysis uncover that, the key factor leading to the crystal phase-dependent performance is the decreased activation barrier of H2O on o-CoSe2 surface. This work opens up an opportunity of correlating the CoSe2 crystal phase with performance in OER.