Preparation of a porous bulk copper ferrite spinel with high performance in the electrolysis of water

Copper ferrite spinels (CFOs) show potential application for use in the field of water electrolysis. However, CFOs are prepared using traditional fabrication methods and as a result always exist in powder form, making them difficult to utilise in applications. In this work, a porous bulk CFO material was fabricated via the milling and sintering of metal oxides, which can be used directly as an electrode. This CFO shows excellent oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) activities. The results show that preparing the CFO under an argon (Ar) atmosphere, at high temperature and with a milling pretreatment improves the density of oxygen vacancies (OVs) in the material, thereby enhancing its ability to electrolyse water. The CFO shows high OER and HER performance when sintered at 1000°C under an Ar atmosphere and milled. In 6 M KOH solution at 10 mA cm −2 , the OER and HER overpotentials of CFO are as low as 290 and 241 mV, with OER and HER Tafel slopes of 75.5 and 114 mV dec −1 . The synthesis route developed in this study is versatile, with the CFO electrode produced exhibiting high performance in water electrolysis.