Water splitting is viewed as a clean substitute for fossil fuels and as the most promising approach for quickly producing hydrogen fuel. The oxygen evolution process (OER), which yields oxygen as the sole byproduct at the anode of a water electrolyzer, also yields hydrogen at the cathode. In this work, we proposed a facile synthetic route to prepare a nanostructured Co-based material for OER via a simple chemical method.

Abstract

To combat with energy crisis considering clean energy, oxygen evolution reaction (OER) is crucial to implement electrolytic hydrogen fuel production in real life. Here, straightforward chemical synthesis pathways are followed to prepare cobalt tetraoxide nanoparticles (Co₃O₄NPs) in an alkaline OER process using poly[(2-methacryloyloxy)ethyl]trimethylammonium chloride (Co₃O₄NPs@PMTC) as support to prevent aggregation. In material characterization, the X-ray diffraction (XRD) pattern confirms the crystallinity of the synthesized Co₃O₄NPs@PMTC, and Raman spectroscopy indicates that the Co₃O₄NPs contain cubic close-packed oxides. The morphological analysis reveals the wrinkle-like disruption which is distributed evenly owing to the folded nanosheet arrays. Energy-dispersive X-ray spectroscopy indicates the presence of a significant number of cobalt atoms in the Co₃O₄NPs, and elemental mapping analysis demonstrates the composition of the NPs. At a current density of 10 mA cm⁻², oxygen is emitted at 1.67 V delivering an overpotential of 440 mV. This unique structure of Co₃O₄NPs@PMTC provides beneficial functions that are responsible for a large number of active sites and the rapid release of oxygen gas with long-term stability. Through kinetic study, we found a Tafel slope of 48.9 mV dec⁻¹ which proves the catalytic behavior of Co₃O₄NPs@PMTC is promising toward the OER process.