Hydrogen energy is at the forefront of the global green energy transition, offering a clean, sustainable alternative to conventional fuels. Efficient water splitting is pivotal for large-scale hydrogen production, yet it demands highly active and durable electrocatalysts. Transition metal selenides have emerged as promising materials due to their superior electrical conductivity, tunable electronic structures, and abundant active sites. A series of CrSe-based catalysts was systematically engineered through controlled Fe incorporation and defect modulation, yielding a CrSe@FeSe2 heterostructure that synergistically enhances intrinsic catalytic activity and interfacial charge transfer. Due to the electronic coupling and the abundance of active sites introduced by vacancy engineering, it exhibited remarkable electrochemical performance in both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The catalyst required an ∼220 mV overpotential to deliver a current density of 20 mA cm–2 for the OER, and 147 mV for HER in an alkaline medium to achieve the same current density. Furthermore, the material demonstrated excellent long-term durability for 40 h, delivering high current densities of 600 mA cm–2 (OER) and 1A cm–2 (HER) in chronoamperometric tests. When used as both an anode and cathode in a two-electrode configuration, the CrSe@FeSe2-based electrolyzer achieved sustained water-splitting performance at 100 mA cm–2 for 40 h with negligible potential degradation. This work highlights the efficacy of vacancy engineering and heterostructure design in optimizing selenium-based transition-metal catalysts for high-performance, durable electrochemical water splitting.
Bhattacharjee et al. (2026) studied this question.