Single Phase Trimetallic Spinel CoCrxRh2-xO4 Nanofibers for Highly Efficient Oxygen Evolution Reaction under Freshwater Mimicking Seawater Conditions

Electrochemical water splitting is a promising pathway for sustainable oxygen production in terms of energy conversion. Seawater electrolysis, especially, is a sustainable approach to carbon-neutral energy conversion without reliance on freshwater; however, extreme corrosion of anodic electrode caused by highly corrosive Cl- is a main challenge of seawater oxidation. To address this issue, herein, nanofibers of trimetallic spinel CoCrxRh2-xO4 with various composition ratios are prepared for highly sustained water oxidation electrocatalysis. Among a series of CoCrxRh2-xO4, CoCr0.7Rh1.3O4 nanofibers exhibit excellent electrocatalytic activity for oxygen evolution reaction (OER): the highest mass activity, the lowest overpotential at 10 mA cm(-2) and the smallest Tafel slope with robust long-term stability under alkaline electrolyte. In addition, CoCr0.7Rh1.3O4 nanofibers deliver better OER performances in simulated seawater than a commercial benchmark catalyst (IrO2 nanoparticles), demonstrating that feasibility of alkaline seawater electrolysis with CoCr0.7Rh1.3O4 nanofibers as an OER electrocatalyst.