Environmentally friendly molten salt synthesis of high-entropy AlCoCrFeNi alloy powder with high catalytic hydrogenation activity

A molten salt synthesis method was used to prepare high-entropy AlCoCrFeNi alloy powder with a high specific surface area of 67.5 m2/g, exhibiting remarkable catalytic activity in the hydrogenation of p-nitrophenol by NaBH4. The life cycle assessment of the proposed method indicated that AlCoCrFeNi production was associated with greenhouse gas emission of 125 kgCO2e/kg-product, whose main contributors were CaH2 and citric acid used during the precursor's reduction and formation, respectively. On the other hand, that for a previously reported dealloying method was 277 kg CO2e/kg-product. Thus, a minimum of 54% greenhouse gas emission reduction compared to the conventional dealloying method is achievable in the proposed molten salt method. The results indicated the possible environmentally friendly production of high-surface-area, high-entropy alloy powders suitable for industrial applications.