In situ construction of pollen-petal-like heterostructured Co3O4–CeO2 on 3D FeNi3 foam as a bifunctional catalyst for overall water splitting

Abstract

The rational design of admirably high-efficiency and relatively stable non-noble metal electrocatalysts is vitally important for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), particularly as bifunctional catalysts for overall water splitting. Herein, via a facile one-pot hydrothermal approach, high-performance bifunctional catalysts of Co₃O₄–CeO₂ with pollen-petal-like heterostructures are synthesized in situ on 3D FeNi₃ foam (FNF) (denoted as Co₃O₄–CeO₂@FNF). In a 1.0 M alkaline aqueous solution of KOH, the designed Co₃O₄–CeO₂@FNF with a large surface area exhibits both outstanding HER and OER activities, with an ultralow overpotential of 53.8 and 236 mV at 10 mA cm⁻², respectively. Additionally, a standard two-electrode system fabricated by employing Co₃O₄–CeO₂@FNF as both the cathode and anode shows an overpotential of 1.59 V at 10 mA cm⁻² and moreover retains 93% of the activity after a 70 h long-term stability test. Moreover, the electron transportation is accelerated due to the increased density of states across the Fermi level resulting from oxygen vacancy doping, which further endows Co₃O₄–CeO₂@FNF with outstanding catalytic performance. Furthermore, it should be noted that the designed catalysts could be manufactured on a large scale, which further envisions their promising commercial utilization for overall water splitting.