Multifunctional catalytic sites regulation of atomic-scale iridium on orthorhombic-CoSe₂ for high efficiency dual-functional alkaline hydrogen evolution and organic degradation

The earth-abundant and high-performance catalysts are crucial for commercial implementation of hydrogen evolution reaction (HER). Herein, a multifunctional site strategy to construct excellent HER catalysts by incorporating iridium (Ir) ions on the atomic scale into orthorhombic-CoSe₂ (Ir-CoSe₂) was reported. Outstanding hydrogen evolution activity in alkaline media such as a low overpotential of 48.7 mV at a current density of 10 mA cm⁻² and better performance than commercial Pt/C catalysts at high current densities were found in the Ir-CoSe₂ samples. In the experiments and theoretical calculations, it was revealed that Ir enabled CoSe₂ to form multifunctional sites to synergistically catalyze alkaline HER by promoting the adsorption and dissociation of H₂O (Ir sites) and optimizing the binding energy for H* on Co sites. It was noticeable that the electrolytic system comprising the Ir-CoSe₂ electrode not only produced hydrogen efficiently via HER, but also degraded organic pollutants (Methylene blue). The cell voltage of the dual-function electrolytic system was 1.58 V at the benchmark current density of 50 mA cm⁻², which was significantly lower than the conventional water splitting voltage. It was indicated that this method was a novel strategy for designing advanced HER electrocatalysts by constructing multifunctional catalytic sites for hydrogen production and organic degradation. © 2024 Science Press