Myung Hwa Kim

Myung Hwa Kim

Affiliation: Ewha Womans University

Research Interests: Chemistry & Nanoscience

Title: Modulation of lattice entropy in a single-phase metal oxide toward sea water splitting reaction

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_xRh_2-xO₄ with various composition ratios are prepared for highly sustained water oxidation electrocatalysis. Among a series of CoCr_xRh_2-xO₄, CoCr_0.7Rh_1.3O₄ 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, CoCr_0.7Rh_1.3O₄ nanofibers deliver better OER performances in simulated seawater than a commercial benchmark catalyst (IrO₂ nanoparticles), demonstrating that feasibility of alkaline seawater electrolysis with CoCr_0.7Rh_1.3O₄ nanofibers as an OER electrocatalyst. Furthermore, we introduce a facile synthetic strategy to grow high entropy unique metal oxide 1-dimensional structures via the combination of an electrospinning process with a simple thermal annealing process. Additionally, their electrochemical performances as efficient electrocatalysts will be discussed for oxygen evolution reaction. This rational engineering of a nanoscale architecture based on the direct formation of the nanostructures on an electrode can offer a useful platform for high performance electrocatalysts, enabling the efficient energy conversion.