Microwave-Assisted Synthesis of a Stainless Steel Mesh-Supported Co₃O₄ Microrod Array As a Highly Efficient Catalyst for Electrochemical Water Oxidation

With the rising energy crisis and increasingly serious environmental issues, clean energy sources like fuel cell and lithium–air batteries are attracting the attention of the whole world. The direct fuel cell, especially, is believed to be the quintessential replacement for conventional sources of energy because of its high energy conversion capacity. Electrochemical water splitting has an important role in such sustainable energy technologies. Catalysts play a worthwhile role in water splitting, especially the oxygen evolution reaction (OER). Engineering fine micro/nanostructures with subtle morphologies represents an effective strategy to enhance the activity of the resultant catalyst toward OER through exposing abundant electrochemically active sites. So, here we report a Co3O4@SUS catalyst, the well-defined Co3O4 microrods were successfully anchored onto the stainless steel mesh substrate with the assistance of diethylenetriamine using microwave irradiation, utilizing a commercially available microwave instrument. Co3O4@SUS possesses outstanding catalytic activity toward water oxidation. In water oxidation, the current density of 10 mA cm–2 was achieved at 298 mV overpotential with a low Tafel slope of 105 mV dec–1. In addition to low overpotential, Co3O4@SUS was stable under conditions of continuous O2 evolution for an extended period (24 h). The results show a highly efficient, scalable, and low-cost method for developing highly active and stable OER electrocatalysts in alkaline solution.