Rethinking Catalysis in Three-Dimensional Topological Materials Through Surface Oxidation.

The catalytic activity of topological materials is often attributed to the nontrivial electronic states of pristine surfaces. However, this interpretation does not explain why chemically and structurally distinct topological compounds frequently exhibit similar catalytic performance despite substantial differences in their band topology. A key limitation of this view is the neglect of surface reconstruction, particularly oxidation under ambient conditions, which can significantly modify both the electronic structure and the nature of active catalytic sites. Here, density functional theory calculations were performed to investigate the energetics of surface oxidation and the hydrogen evolution reaction in representative three-dimensional topological materials, including VAl3, PtGa, PtAl, NbAs, TaAs, and NbP. Surface formation generates highly reactive sites that promote oxygen dissociation and spontaneous oxidation. Although oxidation substantially reconstructs the electronic structure near the Fermi level, favorable hydrogen adsorption energetics are preserved for most compounds and, in some cases, further improved at high hydrogen coverage. These findings identify surface oxidation as a common chemical response across topological materials and provide a unified explanation for their experimentally observed catalytic activity. The results highlight that catalytic performance arises from the combined effects of the parent electronic structure and the chemistry of the oxidized surface, rather than from pristine topological surface states alone.