▎ 摘　　要

Constructing CoO-CoSe2 heterostructures through partial selenization of CoO is proposed to ameliorate the electrocatalytic performance of Co-based compounds toward oxygen evolution reaction (OER). Moreover, with reduced graphene oxide as a platform to in-situ grow N-doped bamboo-like carbon nanotubes encapsulating part of CoO and CoSe2 nanoparticles, we fabricated a novel hybrid (denoted as CoO-CoSe2@N-CNTs/rGO) via a combination of two-stage calcination and subsequent selenization treatment. As an OER electrocatalyst in 1.0 M KOH, CoO-CoSe2@N-CNTs/rGO affords low overpotentials (250 mV@10 mA cm-2 and 322 mV@100 mA cm-2), favorable kinetics (a Tafel slope of 68 mV dec- 1), and excellent durability, outperforming commercial RuO2 and most Co-based electrocatalysts reported till date. Comprehensive experiment results uncover that the exceptional electrocatalytic performance mainly emanates from the synergistic effect between CoSe2 and CoO in heterostructure, N doping effect in CNT and rGO, and the confining effect of N-CNTs and rGO for CoO-CoSe2, resulting in more active sites and enhance conductivity. More importantly, density functional theory calculations disclose that the concurrent N doping and desirable encapsulation of the CoO-CoSe2 nanoparticle in N-CNT can optimize the adsorption energies of OER intermediates and increase the electric conductivity, thereby expediting the OER. This work is helpful to foster understanding on the structure-performance correlations of electrocatalysts with multi-active sites and multi-components for diverse applications.