Scalable synthesis of nanoporous high entropy alloys for electrocatalytic oxygen evolution

High entropy alloys (HEAs) containing five or more equimolar components have shown promising catalytic performance due to their unique chemical and mechanical properties. However, it is still challenging to prepare scalable and efficient nanoporous HEAs as catalysts. Here, we present a facile strategy to synthesize large-scale nanoporous HEAs particles by combing vacuum induction melting, gas atomization, and acidic etching procedure. The application of HEAs to energy conversion is evaluated with electrocatalytic oxygen evolution reaction (OER) on AlCrCuFeNi HEAs. The HEAs exhibit a low OER overpotential of 270 mV to achieve a current density of 10 mA·cm−2, a small Tafel slope of 77.5 mV·dec−1, and long-term stability for over 35 h in 1 mol·L−1 KOH, which is comparable to the state-of-the-art OER electrocatalyst RuO2. The findings in this paper not only provide an industrial approach to produce nanoporous HEAs powder but also inspire the applications of HEAs as catalysts.