Solution combustion synthesis of hierarchical porous CoNiFeCu0.1 medium-entropy alloy: A highly efficient and robust electrocatalyst for water oxidation

The development of efficient and stable oxygen evolution reaction (OER) electrocatalysts with nonprecious materials is still a great challenge for the hydrogen-based energy industry. Here, we report the rational design and effective synthesis of hierarchical porous medium-entropy alloys (MEAs) as promising electrocatalysts for OER via a solution combustion method. Owing to the compositional advantages and unique hierarchical porous structure, the as-prepared CoNiFeCu 0.1 MEA on nickel foam (CoNiFeCu 0.1 @NF) shows superior electrocatalytic performance for OER with an overpotential of about 255 mV at 10 mA cm −2 and a small Tafel slope of 42.7 mV dec −1 in 1.0 M KOH solution. Moreover, it is revealed that the alloying of element Cu in CoNiFe MEA can significantly enhance the charge transfer ability for OER electrocatalysis . The present work shows the hierarchical porous MEAs prepared by solution combustion method have great potential as efficient and robust electrocatalysts for water oxidation in alkaline medium.