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A metastable hexagonal-IrSe2 with activated basal-plane selenium atoms for efficient hydrogen electrocatalysis

Year: 2024

Type: article

Abstract: Developing novel layered transition metal dichalcogenides (TMDs) has gained tremendous interest due to their attractive physicochemical properties and promising applications. Herein, for the first, quasi-monolayered hexagonal -IrSe 2 ( h -IrSe 2 ) nanosheets with metastable two-dimensional structure to the thermodynamically stable orthorhombic counterpart ( o -IrSe 2 ) have been prepared via the colloidal synthesis. Atomic-resolution transmission electron microscopy and spectroscopic characterizations confirm the 1 T configuration of the as-synthesized h -IrSe 2 , constructed from Ir-Se octahedra units. The metastable h -IrSe 2 exhibits significantly enhanced performance for hydrogen evolution/oxidation reactions in alkaline media compared to o -IrSe 2 , even surpassing the metallic Ir nanoparticles . In situ Raman spectra and theoretical calculations reveal that the Se sites on the basal-plane of h -IrSe 2 are the actual active sites. The obtained quasi-monolayered lamellar morphology of h -IrSe 2 provides abundant basal-planes, thereby leading to increased effective electrochemical active area and enhanced mass activity. The activation of the basal-plane Se atoms could be attributed to the reduced local interband energy separation between the lowest empty d -band on Ir and the occupied p -band on Se, which is responsible for the optimized binding strength of the key intermediates during hydrogen electrocatalysis .

Source: Next Materials

DOI: 10.1016/j.nxmate.2024.100463