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, and 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).