Tailoring the electrocatalytic properties of novel microwave synthesized CuNd(2−x)GdxO4 nanoparticles for efficient total water splitting in alkaline media

Abstract

Electrocatalytic water splitting, powered by renewable energy, has emerged as a promising avenue towards a hydrogen-based energy future. Strategic engineering of electrocatalyst properties is crucial for achieving high efficiency in water electrolyzers. Capitalizing on the catalytic properties of rare earth metals, we propose a novel microwave-synthesized CuNd_(2−x)Gd_xO₄ nanoparticles as an efficient electrocatalyst for total water splitting. The catalyst exhibits a pronounced correlation between gadolinium loading concentration and the activity of both OER and HER. A concentration-dependent, volcano-shaped relationship between electronic charge and thermoneutral current densities was observed. The optimal CuNd_1.7Gd_0.3O₄ nanoparticles require overpotentials of 243 and 118 mV for OER and HER, respectively to achieve a current density of 10 mA cm⁻² in 1 M KOH with 50 h of long-term stability. The catalyst's exceptional ability is further demonstrated by its application in total water splitting, employing CuNd_1.7Gd_0.3O₄ as both anode and cathode electrocatalysts. It achieves an impressive cell voltage of 1.62 V at 10 mA cm⁻² with a 60 h stability. This remarkable achievement is primarily attributed to gadolinium doping, which optimizes the electrocatalyst's charge transfer for both oxygen and hydrogen evolution reactions. This study provides a foundation for developing advanced electrocatalysts tailored for efficient total water splitting.