Dual-phase engineering in Ti-modified CoCrFeNi₂ high-entropy alloys for efficient hydrogen and oxygen evolution reaction

Abstract

The demand for sustainable and clean energy sources has intensified research into hydrogen production via electrocatalytic water splitting, a favorable process for generating high-purity hydrogen. While previous research has largely focused on optimizing the composition of catalysts, our work demonstrates the critical role of morphology in enhancing catalytic activity. High entropy alloys (HEAs), characterized by their multi-component equiatomic compositions, have materialized as hopeful catalysts due to their sole chemical and structural properties. This study explores the catalytic performance of CoCrFeNi₂Ti<inf>x</inf> (x = 0, 0.3, 0.5, 0.8, 1) HEAs with varying titanium (Ti) compositions for effective hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The optimized morphology of the CoCrFeNi<inf>2</inf>Ti<inf>0.5</inf> HEA led to lower overpotential and favorable Tafel slopes, achieving a current density of 10 mA cm−2, in alkaline media with superior stability. Our findings reveal that the synergistic effects of composition and morphology are crucial in developing high-performance catalysts for viable hydrogen generation. This work offers critical comprehension into design/morphology and application of HEAs in energy conversion technologies, offering an auguring pathway for the formulation of efficient and durable water-splitting catalysts. © 2025 Elsevier B.V., All rights reserved.