Lattice strain assisted with interface engineering for designing efficient CoSe2-CoO core-shell microspheres as promising electrocatalysts towards overall water splitting

Abstract

Cobalt-based oxides hold immense potential recognized as innovative electrocatalysts in the field of overall water splitting. Nevertheless, the unsatisfactory activity induced by low conductivity remains a significant challenge. Herein, a facile lattice strain strategy assisted with interface engineering is triggered in this work with the aim to circumvent the mentioned drawback. Specifically, a novel liquid nitrogen quenching treatment combined with selenic acid etching/doping strategy is proposed to prepare cobalt glycerolate template derived CoSe2-CoO core-shell microspheres synergetic modulated by lattice tensile strain and interface engineering (named as TS-CoSe2-CoO CSM). Moreover, the electrochemical properties influenced by lattice tensile strain and interface are systematically studied and explored. The lattice tensile strain could tailor the surface electronic structure, interface engineering could adjust electronic structure of the active sites. Moreover, the unique core-shell structure furnishes high specific area and short ions/electrons transmission path. Surprisingly, the TS-CoSe2-CoO CSM could catalyze HER and OER with a small overpotential of 71.5 mV and 257.6 mV at 10 mA/cm2, respectively. Importantly, the electrolytic tank using the bifunctional catalyst reveals outstanding performance by requiring 1.36 V at 10 mA/cm2, outperforming most of the reported Co-based bifunctional catalysts. Overall, this work could provide valuable insights to build advanced electrocatalysts for abroad applications.