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

• The Bi/Cu(1 1 1) interface shows enhanced activity towards CO 2 activation with the synergetic effect as compared to Cu(1 1 1) • The interfacial structure is demonstrated to be important for the CO 2 dissociation by forming the Bi-O-Cu heterostructure. • Further formation of Cu + induced by the defective oxygen from the decomposition of Bi oxide promotes the dissociation of CO 2 . Thermocatalytic CO 2 reduction reaction (CO 2 RR) is one of the promising strategies to mitigate CO 2 emissions. Meanwhile, understanding the reduction mechanism of CO 2 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 CO 2 RR 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 CO 2 exposure, Bi is oxidized at interface due to the activation of CO 2 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(1 1 1), 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 CO 2 . 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 CO 2 RR.