Surface Van Hove Singularity Enabled Efficient Catalysis in Low-Dimensional Systems: CO Oxidation and Hydrogen Evolution Reactions.

Surface Van Hove singularity (SVHS) triggers exciting physical phenomena distinct from the bulk. Herein, we explore the potential role of SVHS in catalysis for both CO oxidation and the hydrogen evolution reaction (HER) using the graphene/Ca 2 N (Gra/Ca 2 N) heterojunction and Pt 2 HgSe 3 (001) surface as prototype systems. It is demonstrated that both systems with SVHS could serve as an electron bath to promote O 2 adsorption and subsequent CO oxidation with low energy barriers of 0.2-0.6 eV for the Gra/Ca 2 N and Pt 2 HgSe 3 (001) surface and similarly facilitate the HER with near-zero hydrogen adsorption free energy. Importantly, the catalytically active sites associated with SVHS are well-defined and distributed over the whole surface plane, and further, the chemical reactivity of SVHS can also be tuned easily via adjusting its position with respect to E F . Our study demonstrates the enabling power of SVHS and provides novel physical insights into the promising potential role of VHS in designing high-efficiency catalysts.