Ampere-level oxygen evolution reaction driven by Co3O4nanoparticles supported on layered TiO2Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d4cy00557k

Cobalt oxide (Co3O4) is an attractive catalyst for the oxygen evolution reaction (OER). However, the OER performance of previously reported Co3O4nanoparticles is insufficient for ampere-level current. The reason is the lack of covalent bonds between Co3O4nanoparticles and the substrate, which leads to a high electron transfer energy barrier. Herein, Co3O4nanoparticles supported on a layered TiO2surface (Co3O4@layered-TiO2) by Co–O–Ti covalent bonds are carefully constructed through the MXene precursor method. As a result, Co3O4@layered-TiO2exhibits 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.