Facile synthesis of Ir-based high-entropy alloy nanomaterials for efficient oxygen evolution electrocatalysis

J Colloid Interface Sci. 2024 Dec 19;683(Pt 1):1096-1105. doi: 10.1016/j.jcis.2024.12.147. Online ahead of print.

Abstract

High-entropy alloy (HEA) nanomaterials have emerged as promising candidates as oxygen evolution reaction (OER) electrocatalyst to overcome the existing issues of the sluggish reaction kinetics and poor stability. In this study, IrxRuCoCuNi HEA three-dimensional-nanoframeworks (3DNF) are prepared using a scalable approach-the spray-drying technique combined with thermal decomposition reduction (SD-TDR). The optimized catalyst, Ir2RuCoCuNi, demonstrates superior OER performance, with an overpotential of 264 mV at 10 mA cm-2 and a Tafel slope of 47 mV dec-1, considerably surpassing the catalytic activity of commercial IrO2. Electrochemical data reveal high electron transfer efficiency and a significant electrochemically active surface area (ECSA), attributed to its 3DNF porous structure and favorable surface self-reconstruction into (oxy)hydroxides during the OER. While increasing Ir content enhances catalytic activity, economic analysis highlights compositions with reduced Ir content, such as IrRu2CoCuNi and IrRuCo2CuNi, as cost-effective alternatives for practical applications. These findings underscore the potential of HEA 3DNFs for industrial-scale electrocatalysis and provide insights into balancing performance and cost for next-generation OER catalysts.

Keywords: Alkaline water electrolysis; Ir-based high-entropy alloy nanomaterials; Spray drying and thermal decomposition reduction method; Superior electrocatalytic performance; Three-dimensional nanoframeworks.