Porous hollow nanorod structured chromium-substituted inverse spinel compound: An efficient oxygen evolution reaction catalyst

[Display omitted] •The electro-spun derived inverse spinel oxides: NiCrxFe2-xO4 (x: 0 and 1) materials examined of OER studies.•The developed materials displayed porous hollow nanorod-shaped structure.•The Cr-substituted spinel delivered a low η value of 296 mV at 10 mA cm−2 in 1 M KOH.•The Tafel value of Cr-substituted spinel outperformed the state-of-the-art commercial RuO2.•The nanostructured spinel material accomplished a long-term stability of 14 h at 10 mA cm−2. Spinel-based oxygen evolution reaction (OER) catalyst using various cation substitution strategies is gained importance due to its improved catalyst performance. Herein, we report the chromium (Cr)-substituted nickel ferrite, inverse spinel compound (NiCrFeO4) of porous hollow nanostructure using a simple electrospinning approach. The developed inverse spinel compound displays a nanorod-shaped nanostructure of an overall diameter of 60 ± 10 nm and an inner hollow thickness of 30 ± 10 nm. In this study, the Cr-substituted catalyst delivers an overpotential value of 298 mV which is lower than the developed electrospun-based Cr-free NiFe2O4 (330 mV) and the commercial-based NiFe2O4 (330 mV) compound at 10 mA cm−1 under 1 M KOH. Further, the Cr-substituted catalyst exhibits a low Tafel slope value of 44.7 mV dec-1 than the RuO2 catalyst (63.7 mV dec-1). In addition, the catalyst is able to deliver excellent OER durability of 14 hrs at voltage retention of 94.5 % at 10 mA cm−2 condition. In this study, a simple method and a favorable nanostructure to unveil a potential OER candidate are developed.