Highly active hydrogen evolution facilitated by topological surface states on a Pd/SnTe heterostructure

Topological quantum materials have emerged as promising electro-catalysts for hydrogen evolution reaction (HER). However, most of their performance is behind noble metals such as benchmark platinum (Pt). Here, we report a molecular-beam-epitaxy-and electron-beam-evaporation-grown Pd(20nm)/SnTe(70nm) hetero-structure that displays a higher electrocatalytic activity than that of a pure Pd(20nm) thin film, and higher than that of a commercial Pt foil. Density functional theory calculations show that the topolog-ical surface states (TSSs) of the SnTe (001) play a key role. Electron transfer from both Pd and adsorbed H atoms to the TSSs results in weaker Pd-H binding and more favorable DGH. Our work demon-strates that a metal/topological material heterostructure could be a prominent catalyst to enjoy HER activity outperforming that of Pt and offers a promising direction to optimize the performance of electrocatalysts based on topological quantum materials.