Synthesis of unsupported two-dimensional molybdenum carbide nanosheets for hydrogen evolution

Abstract A method was developed for the synthesis of multi-layered and single-layered molybdenum carbide (β-Mo2C) nanosheets through exfoliation and centrifugation of a layered oxide precursor. The single-layer materials displayed higher intrinsic activity for the hydrogen evolution reaction (59.3 ± 6 mA/mg vs 5.3 ± 2 mA/mg) compared to the multi-layered carbide nanosheets. This effect was attributed both to high surface areas and to a more reactive surface where the binding energy of *H is optimized for the HER.