While hydrogen does represent a promising form of green energy storage, the sluggish kinetics of the water splitting reaction limits the efficiency and the practical implementation of electrolytic water splitting and green hydrogen production on an industrial scale . The current state-of-theart materials for OER catalysis often contain materials like IrO2 and RuO2 2,3 . RuO2 for example, typically has overpotentials between 250-350mV at 10mA/cm 2 of current density and Tafel slopes between 50-70 mV.dec -1 in basic conditions of 1M KOH . However, IrO2 and RuO2 are rare and expensive, necessitating the development of cheaper catalysts that are comparable to them on both metrics. Spinels can potentially replace IrO2 and RuO2 with earth-abundant metal oxide catalysts capable of catalysing OER . The crystal structure of spinel oxides is made up of oxygen anions arranged within a cubic close-packed sublattice while metallic cations are positioned within the tetrahedral and octahedral interstitial sites between the anions . The basic composition of a ternary-phase spinel oxide is AxB3-xO4, where A and B are two different metals . In this structure, the distribution of both metals across both coordination geometries can be represented by the formula (Ax-εB1-x+ε)Td(AεB2-ε)Oh where Td refers to tetrahedrally coordinated cations, Oh refers to octahedrally coordinated cations and ε refers to the inversion parameter (ε = 0x) (Figure ). If ε equals 0, the structure is a normal spinel, and if ε equals x, the structure is an inverse spinel . The presence of transition metals in both the AO4 and BO6 structural units likely allows both of them to contribute to OER activity. This could potentially increase the structural diversity and tunability of spinel oxide catalysts for OER catalysis, making them an interesting system to study.