Chemical dealloying derived nanoporous FeCoNiCuTi high-entropy bifunctional electrocatalysts for highly efficient overall water splitting under alkaline conditions

In response to society's urgent drive to significantly decrease its reliance on fossil fuels in the future, there has been continuing efforts to utilize hydrogen (H2) generated by water electrolysis as clean and sustainable substitute for the traditional fossil fuels. A significant challenge in water electrolysis revolves around creating affordable and efficient electrocatalysts to speed up the chemical reactions involved. Our new study introduces a bifunctional catalyst made from a high-entropy alloy (HEA), capable of efficiently catalyzing both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The findings reveal that a complex chemical composition of FeCoNiCuTi HEA can significantly modify its electronic structure, resulting in an impressive electrocatalytic performance. Specifically, FeCoNiCuTi HEA catalyst exhibits an overpotential of 64.9 mV at a current density of 10 mA cm−2 for hydrogen evolution with a Tafel slope of 36.81 mV dec−1 and double-layer capacitance (Cdl) of 34.1 mF cm−2. For oxygen evolution, HEA achieves an overpotential of 175 mV at 10 mA cm−2, a Tafel slope of 44.31 mV dec−1, exhibiting the performance superior to noble catalysts. Theoretical calculations support that the intricate chemical composition of high-entropy alloy plays vital role to enhance its electrocatalytic capabilities. This research represents a straightforward efficient method to create electrocatalysts for water electrolysis using non-noble metals by leveraging high-entropy effect.