Single Phase Trimetallic Spinel CoCr<i><sub>x</sub></i>Rh<sub>2‐</sub><i><sub>x</sub></i>O<sub>4</sub> Nanofibers for Highly Efficient Oxygen Evolution Reaction under Freshwater Mimicking Seawater Conditions
Dasol Jin, Hyerim Woo, Sampath Prabhakaran, Youngmi Lee, Myung Hwa Kim, Do Hwan Kim, Chongmok Lee
Abstract
Abstract 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 CoCr x Rh 2‐ x O 4 with various composition ratios are prepared for highly sustained water oxidation electrocatalysis. Among a series of CoCr x Rh 2‐ x O 4 , CoCr 0.7 Rh 1.3 O 4 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, CoCr 0.7 Rh 1.3 O 4 nanofibers deliver better OER performances in simulated seawater than a commercial benchmark catalyst (IrO 2 nanoparticles), demonstrating that feasibility of alkaline seawater electrolysis with CoCr 0.7 Rh 1.3 O 4 nanofibers as an OER electrocatalyst.