Fe-doped Co3O4 nanostructures prepared via hard-template method and used for the oxygen evolution reaction in alkaline media

Low-cost and highly efficient anode catalysts are required for the oxygen evolution reaction (OER), which is integral to the commercialization of alkaline-based water electrolysis. Herein, pore size-controlled Fe -doped Co3O4 nanostructures are prepared as non-precious metal anode catalysts using a hard-template method with silica beads of different sizes, ranging from 20 to 1000 nm in diameter. The pore size dis-tribution and specific surface area of the catalysts are measured by nitrogen adsorption/desorption anal-ysis and mercury intrusion porosimetry. The electrochemical properties and OER performances of the catalysts are evaluated in half and unit cells, respectively. Among the catalysts studied, FCO-T-500 syn-thesized using 500 nm-sized silica beads exhibits the best OER activity and stability, given by a high cur-rent density of 847 mA cm-2 at 1.8 V and superior 100 h-stability during single cell test of anion exchange membrane water electrolysis. The improved OER performance of FCO-T-500 can be attributed to the opti-mal pore size favorable for gas diffusion and mass transport, sufficient surface OH and H2O groups pro-duced via KOH leaching, the largest number of electrocatalytic active sites, and the fastest charge-transfer reaction. (c) 2023 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.