Synergistic Enhancement of Oxygen Evolution by S-Ti₃C₂Tx MXene Folded Nanosheets Supported by Cobalt Hydroxide Nanoparticles

The metal active site-induced adsorbate evolution mechanism (AEM) and the lattice oxygen-mediated mechanism (LOM) can significantly improve the performance of the electrocatalytic oxygen evolution reaction, but the LOM is not easily triggered on the AEM. Herein, a unique mixture of transition metal Ti3C2Tx MXene and cobalt hydroxide is introduced. A sulfur-doped Ti3C2Tx MXene substrate with a clear composition and layered structure was formed on Ti3C2Tx MXene thin-layer nanosheets by the sulfur template method for the study of alkaline electrochemical oxygen evolution. Sufficient metal active sites, robust structures, good electrochemical kinetics, and increased catalytic activity are provided by the resulting nanohybrids. Significantly, the sulfur-doped MXene substrate has more abundant oxygen vacancies and better hydrophilicity; this interaction is more favorable for improving the electrochemical performance of the alkaline oxygen evolution reaction (OER). The results of electrochemical tests support the hypothesis that the interfacial electron coupling of two different components and the doping of the oxygen vacancy may optimize the adsorption energy of H2O and *OH, leading to a small overpotential of 207 mV at 10 mA cm–2, and the material is stable for the OER. This has great potential for the development of electrocatalysts where both the AEM and the LOM work together and their applications in energy-related fields.