Transition metals of Pt and Pd on the surface of topological insulator Bi2Se3.

Transition metal catalysts supported on topological insulators are predicted to show improved catalytic properties due to the presence of topological surface states, which may float up to the catalysts and provide robust electron transfer. However, experimental studies of surface structures and corresponding catalytic properties of transition metal/topological insulator heterostructures have not been demonstrated so far. Here, we report the structures, chemical states, and adsorption behaviors of two conventional transition metal catalysts, Pt and Pd, on the surface of Bi₂Se₃, a common topological insulator material. We reveal that Pt forms nanoparticles on the Bi₂Se₃ surface. Moreover, the interaction between Pt and surface Se is observed. Furthermore, thermal dosing of O₂ onto the Pt/Bi₂Se₃ heterostructure leads to no oxygen adsorption. Detailed scanning tunneling microscopy study indicates that Pt transforms into PtSe₂ after the thermal process, thus preventing O₂ from adsorption. For another transition metal Pd, it exhibits approximate layer-island growth on Bi₂Se₃, and Pd–Se interaction is also observed. Our work provides significant insights into the behaviors of transition metals on top of a common topological insulator material and will assist in the future design of catalysts built with topological materials. [ABSTRACT FROM AUTHOR]