DFT insight into the effect of Cu atoms on adsorption and dissociation of CO over a Pd/ TiO(101) surface

In order to improve the photocatalytic activity of a bimetallic cocatalyst, understanding its mechanism is very important for the development of a CO 2 photocatalyst. In this study, density functional theory (DFT) calculations were performed to investigate CO 2 adsorption and dissociation over Pd-Cu bimetallic clusters loaded on a TiO 2 (101) surface, aiming at understanding the origin of the effect caused by the presence of Cu. The results demonstrated that the introduction of a Cu atom has a dual effect on the adsorption and dissociation of CO 2 : (1) it provides the positive polarization charge center to enhance CO 2 adsorption, and (2) it up-shifts the d-band center of the Cu atom to improve the activation of CO 2 . Thus, the activity of the Pd 7 Cu 1 /TiO 2 (101) surface, as compared with that of the Pd 8 /TiO 2 (101) surface, can be significantly improved, and the active center is the introduced Cu atom. This result is not only helpful for the development of effective CO 2 photocatalysts but also crucial to understand the basic mechanism of bimetallic catalysis. The Cu atom provides the positive polarization charge center to enhance CO 2 adsorption and up-shifts its d-band center to improve the activation of CO 2 .