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

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.