Interfacial Engineering of CuSe2/FeSe2 Heterojunction for Water Splitting: A Pathway to High-Performance Hydrogen and Oxygen Evolution Reactions

Abstract

The efficiency of green hydrogen production via water electrolysis is critically constrained by high energy barriers, particularly during the oxygen evolution reaction (OER). In this study, CuSe2/FeSe2 heterojunctions are introduced as cost-effective and highly active bifunctional electrocatalysts for overall water splitting. Leveraging the abundant and tunable properties of Cu- and Fe-based chalcogenides, this work demonstrates how charge redistribution and interfacial electronic coupling in the heterostructure significantly enhance catalytic activity. The high surface area CuSe2/FeSe2 heterojunction enhances hydrogen and oxygen adsorption and accelerates charge transfer, achieving low overpotentials (666 mV for HER, 490 mV for OER at 10 mA cm-2), a high OER current density (135 mA cm-2), and a reduced Tafel slope (137 mV dec-1). The catalyst maintained stable performance over 24 hours of continuous operation at 10 mA cm-2, confirming its structural robustness and practical viability. These findings position CuSe2/FeSe2 heterojunctions as promising candidates for scalable, sustainable hydrogen production and advanced electrochemical energy technologies.