Defect and interface engineering of templated synthesis of hollow porous Co3O4/CoMoO4 with highly enhanced electrocatalytic activity for oxygen evolution reaction

The development of oxygen evolution reaction (OER) electrocatalyst with high efficiency, low cost and robust stability is of great significance for practical water electrolysis. Herein, a series of hollow porous Co3O4/CoMoO4 hybrids were synthesized based on defect, interface and nano/microstructure engineering. The comprehensive engineering greatly improved number and activity of active sites, mass and charge transfer of the catalysts. The catalysts consequently exhibited excellent electrocatalytic activities for OER under alkaline conditions. Especially, the optimum Co3O4/CoMoO4-0.1-FO catalyst exhibited ultralow overpotential of 342 mV to afford a current density of 100 mA·cm−2 and a small Tafel slope of 72 mV·dec–1. The theoretical calculations revealed that the defect and interface engineering can effectively adjust the adsorption energy of the reactive sites to intermediates and greatly decrease energy barrier of the Co3O4/CoMoO4 in the process of OER, and consequently increase the OER activity. This work supplied a vivid example to fabricate highly effective composite catalysts by comprehensive employing multiple engineering.