In situ Raman study on the impact of configurational entropy on catalytic activity for industrial water oxidation

Abstract

Modulating the configurational entropy of materials is an effective strategy to develop efficient and robust electrocatalysts for the oxygen evolution reaction (OER) in clean energy technologies. However, the impact of configurational entropy on catalytic activity has received limited attention. In this study, we systematically investigate a class of alloy catalysts composed of Cr, Mn, Fe, Co, and Ni, as a function of Ni content to modulate the configurational entropy to 1.50R (high-entropy alloy, Ni-HEA), 1.23R (medium-entropy alloy, Ni-MEA), and 0.66R (low-entropy alloy, Ni-LEA), where R is 8.314 J (mol⁻¹ K⁻¹). In situ Raman spectroscopy reveals that increased configurational entropy facilitates the formation of the OER active γ-NiOOH phase on the alloy surface. This transition leads to a significant decrease in the OER overpotentials and Tafel slopes. The optimized Ni-HEA exhibits an overpotential of only 217 mV at 10 mA cm⁻², and demonstrates prolonged operational stability for 600 hours under industrial conditions. This work enhances our understanding of the impact of configurational entropy on catalytic activity and offers a novel approach for the rational design of porous high-entropy catalysts with improved OER efficiency.