Enhanced dissociation activation of CO2 on the Bi/Cu(1 1 1) interface by the synergistic effect

Thermocatalytic CO2 reduction reaction (CO2RR) is one of the promising strategies to mitigate CO2 emissions. Meanwhile, understanding the reduction mechanism of CO2 on the catalyst surface is imperative for advancing catalyst design and the eventual industrialization under mild conditions. In this work, the catalytic role of bismuth/copper interface towards CO2RR is elaborately investigated via a combination of near ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS), ambient-pressure scanning tunneling microscopy (NAP-STM) and density function theory (DFT). It is demonstrated that the initial deposition of Bi on Cu results in the formation of Bi-Cu heterogenous structure, while the interface is buried at the thick coverage. Upon CO2 exposure, Bi is oxidized at interface due to the activation of CO2 on Cu sites and subsequent migration of oxygen to Bi, while Cu+ is induced afterwards in annealing acting as the further dissociation site. Compared with the pure Cu(111), the fraction of oxidation including both lattice and defective oxygen is significantly higher on the Bi/Cu interface, indicating the synergistic effect of Bi-Cu interface in the activation of CO2. Thus, our work clearly reveals the dissociation site evolution of the Bi-Cu bimetallic heterostructure and might promote the design of Cu-based catalysts for advancing thermocatalytic CO2RR.