Template-Free\nSynthesis of High-Surface-Area Co<sub>3</sub>O<sub>4</sub> Nanomaterials\nfrom Perovskite Precursors (ACoO<sub>3</sub>, A: La and Sr) for Efficient\nWater Oxidation

Developing\nlow-cost and highly active oxygen evolution reaction\n(OER) electrocatalysts using earth-abundant elements through simple\nand efficient synthesis methods holds paramount importance for sustainable\nhydrogen production via water electrolysis. Porous catalyst materials\nhave proven versatile in heterogeneous catalysis due to their high\nsurface area and fast mass diffusion. Herein, we developed a simple\nand sustainable approach for synthesizing high-surface-area, porous\nCo<sub>3</sub>O<sub>4</sub> nanomaterials from perovskite materials,\ni.e., SrCoO<sub>3</sub> and LaCoO<sub>3</sub>. The resulting porous\nCo<sub>3</sub>O<sub>4</sub> nanomaterials exhibit exceptional efficiency\nin the water oxidation reaction. Notably, the acid-treated sample\n(AT-SCO-1M) demonstrated superior photochemical and electrochemical\nactivities. It exhibits a high turnover frequency (TOF) of 8.13 ×\n10<sup>–3</sup> s<sup>–1</sup>, along with a lower overpotential\n(375 mV) and Tafel slope (117 mV/dec) compared to the untreated Cg-Co<sub>3</sub>O<sub>4</sub> nanoparticles (4.28 × 10<sup>–3</sup> s<sup>–1</sup>, 465 mV, and 220 mV/dec). This method’s\nselective removal of A-site cations from the perovskite precursors\nincreases the catalyst surface area, porosity, and hydrophilicity,\nall collectively contributing to improved water oxidation activity.\nOur sustainable approach for synthesizing high-surface-area, porous\nnanomaterials through a simple, environmental, and recyclable method\nshows a new way to design highly active water oxidation catalysts\nand other catalytic applications.