Investigating Layered Topological Magnetic Materials as Efficient Electrocatalysts for Hydrogen Evolution Reaction Under High Current Densities

Despite significant progress in the catalyst development for hydrogen generation with highly efficient performances, there is still a lack of durable catalysts operating under large current densities (i.e., > 1000 mA/cm²). Therefore, in search of efficient cost-effective PGM-free electrocatalysts for sustainable clean energy this work investigates the catalytic behavior of emergent layered quantum ferromagnetic semiconducting materials for hydrogen evolution reaction (HER). Specifically, the materials of interest include transition metal trihalide (i.e., CrCl₃, VCl₃, VI₃, and VI₂) multilayers and for a given structural unit, the layered structure is formed by tri-layers where Cr (or V) atoms is sandwiched between two halide layers. A few layers of these crystals were exfoliated on conducting substrates and electroanalytical tests were conducted for HER in both acidic and alkaline media. We find that the HER evolves systematically with changing halogen atom (Cl or I). Our results demonstrate reasonable activities for all the materials under 1000 mA/cm² requiring overpotentials ranging around 233-281 and 245-297 mV in 0.5M H₂SO₄ and 1M KOH electrolytes, respectively. The weak interlayer coupling, spontaneous surface oxidation (e.g., O-CrCl₃), intrinsic Cl or I vacancy defects or presence of bulk oxygen giving rise to in-gap states and sufficiently conductive support interaction lowering charge transfer resistance endow interesting electrocatalytic properties of which the novel structure-to-electrochemical property relations is established. Such behavior would be extrapolated to monolayers for further demonstration and these findings exemplify the critical role of substrate and significant potential for designing industrial-relevant HER electrocatalysts.