Abstract
Materials carrying topological surface states (TSS) provide a fascinating platform for the hydrogen evolution reaction (HER). Based on systematic first-principles calculations for ( = Ni, Pd, Pt; = Si, Ge, Sn), we propose that topological electric polarization characterized by the Zak phase can be crucial to designing efficient catalysts for the HER. For , we show that the Zak phase takes a nontrivial value of in the whole (111) projected Brillouin zone, which causes quantized electric polarization charges at the surface. There, depending on the adsorption sites, the hydrogen (H) atom hybridizes with the TSS rather than with the bulk states. When the hybridization has an intermediate character between the covalent and ionic bonds, the H states are localized in the energy spectrum, and the change in the Gibbs free energy () due to the H adsorption becomes small. Namely, the interaction between the H states and the substrate becomes considerably weak, which is a highly favorable situation for the HER. Notably, we show that for and are just and eV, respectively, which are almost half of the value of Pt.
- Received 13 July 2022
- Accepted 3 October 2022
DOI:https://doi.org/10.1103/PhysRevB.106.165120
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