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

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, Ir_xRuCoCuNi 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.