Ampere-level oxygen evolution reaction driven by Co3O4 nanoparticles supported on layered TiO2

Abstract

Cobalt oxide (Co₃O₄) is an attractive catalyst for the oxygen evolution reaction (OER). However, the OER performance of previously reported Co₃O₄ nanoparticles is insufficient for ampere-level current. The reason is the lack of covalent bonds between Co₃O₄ nanoparticles and the substrate, which leads to a high electron transfer energy barrier. Herein, Co₃O₄ nanoparticles supported on a layered TiO₂ surface (Co₃O₄@layered-TiO₂) by Co–O–Ti covalent bonds are carefully constructed through the MXene precursor method. As a result, Co₃O₄@layered-TiO₂ exhibits brilliant OER performance with ultra-low potential (1.52 V to reach 100 mA cm⁻²), ampere-level current density (1.66 V to reach 1000 mA cm⁻²) and long-term durability (110 h at 500 mA cm⁻²). Density functional theory studies have confirmed that the Co–O–Ti covalent bonds can adjust the d band center to optimize reaction energy barriers. This result illuminates a new strategy for constructing highly active materials on the metal oxide substrate for efficient electrocatalysis.