Benchmark comparison of Co3O4 spinel-structured oxides with different morphologies for oxygen evolution reaction under alkaline conditions

In this work a series of Co3O4 spinels were produced by different synthesis routes (precipitation, solution combustion synthesis, hard template method), and were used as non-noble catalysts for the oxygen evolution reaction (OER) under basic conditions. The investigated catalysts have a proportional relation between electrochemical activity, surface roughness and specific surface area. The hard-template synthesis method resulted in the most active catalyst compared in this work, which we ascribe to its highly porous structure, and concomitant Co3+/Co4+ redox couple at a lower potential, attributed to the OER. The most performant catalyst was compared with a commercial catalyst (Ni@NiO, Alfa Aesar) showing only 0.01 V overpotential difference, evaluated at 10 mA·cm–2 (overpotential 0.44 V).