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.

Automated summary

In this study, nanofibers of CoCrxRh2-xO4 were prepared to address the main challenge of anodic electrode corrosion in seawater electrolysis. Among the series of CoCrxRh2-xO4, CoCr0.7Rh1.3O4 nanofibers exhibited excellent electrocatalytic activity for oxygen evolution reaction with the highest mass activity, lowest overpotential, and smallest Tafel slope. In addition, CoCr0.7Rh1.3O4 nanofibers showed better OER performances in simulated seawater than a commercial benchmark catalyst (IrO2 nanoparticles), demonstrating their feasibility as an OER electrocatalyst for seawater electrolysis.