A Universal CoO/CoSe2 Heterostructure Electrocatalyst towards Hydrogen Evolution Reaction via In-situ Partial Surface-Oxidation-Selenization Method

Abstract In-situ engineered heterogeneous transition metal electrocatalysts with excellent hydrogen evolution reaction performance are generally challengeable in the domain of electrocatalysis. Here, we provide a robust CoO/CoSe2 hybrid electrocatalyst towards hydrogen evolution reaction in a wider pH limits through an effective in situ partial surface-oxidation-selenization route. The purpose and ideas of the design are elaborated by the clever use of the process of partial transforming MOFs to LDHs, in situ growing ZnCo-LDHs on the surface of ZIF-8, increasing the number of oxygen-containing groups on the surface of MOFs to achieve more Co and subsequent CoO, and constructing CoO/CoSe2 heterostructure materials by further selenization. More importantly, the CoO/CoSe2 nanoparticles is encapsulated with in-situ grown nitrogen-doped graphitized carbon shell and embedded in N, Se co-doped carbon network. Owing to the well-designed nanostructure and the synergistic effect from CoO and CoSe2, this hybrid electrocatalyst show substantially enhanced activity and improved long-term durability beyond CoO under both acid and alkaline conditions. This research work may pave a new avenue for the design of universal CoO-based electrocatalysts and their application in clean energy related fields.