Template-Free Synthesis of High-Surface-Area Co3O4 Nanomaterials from Perovskite Precursors (ACoO3, A: La and Sr) for Efficient Water Oxidation

Developing low-cost and highly active oxygen evolution reaction (OER) electrocatalysts using earth-abundant elements through simple and efficient synthesis methods holds paramount importance for sustainable hydrogen production via water electrolysis. Porous catalyst materials have proven versatile in heterogeneous catalysis due to their high surface area and fast mass diffusion. Herein, we developed a simple and sustainable approach for synthesizing high-surface-area, porous Co3O4 nanomaterials from perovskite materials, i.e., SrCoO3 and LaCoO3. The resulting porous Co3O4 nanomaterials exhibit exceptional efficiency in the water oxidation reaction. Notably, the acid-treated sample (AT-SCO-1M) demonstrated superior photochemical and electrochemical activities. It exhibits a high turnover frequency (TOF) of 8.13 x 10-3 s-1, along with a lower overpotential (375 mV) and Tafel slope (117 mV/dec) compared to the untreated Cg-Co3O4 nanoparticles (4.28 x 10-3 s-1, 465 mV, and 220 mV/dec). This method's selective removal of A-site cations from the perovskite precursors increases the catalyst surface area, porosity, and hydrophilicity, all collectively contributing to improved water oxidation activity. Our sustainable approach for synthesizing high-surface-area, porous nanomaterials through a simple, environmental, and recyclable method shows a new way to design highly active water oxidation catalysts and other catalytic applications.