Stable High-Entropy Alloy AlCoCrFeNi2.1 with Anti-Dealloying Effect for Enhanced Oxygen Evolution Performance

The catalytic performance of oxygen evolution reaction (OER) catalysts is influenced by their elemental composition. Aluminum (Al) offers abundant active sites due to its high oxidation affinity, which makes it unstable in both acidic and alkaline environments. We used the gas atomization method (GAM) to prepare the aluminum-containing single-phase high-entropy alloy AlxCoCrFeNi2.1 (x = 0, 0.1, 0.3, 0.5, 1). Besides, changing the aluminum content in the HEAs can control the alloy particle size. The GAM can enable the HEAs with different Al contents to present the body-centered cubic (BCC) structure, avoiding alloy phase separation caused by other component contents in the smelting method. As predicted by theory, as aluminum content increases, the AlCoCrFeNi2.1 shows the best OER performance (overpotential ≈313 mV for 1000 h at 100 mA·cm–2). Furthermore, through the precise weight detection system, COMSOL simulations, and Density Functional Theory (DFT) calculations, we have further demonstrated the superiority of AlCoCrFeNi2.1 catalysis. Overall, this work provides a streamlined way to slow down the dissolution of oxygen catalysts for water electrolysis and contributes a controllable choice for more element-dependent scenarios.