Edge-confined Pt single atoms on 2D-MoS2 nanosheets with a synergetic mechanism for CO2 conversion

Single-atom catalysts (SACs) with a two-dimensional (2D) material as the support offer peculiar active sites at edges and in planes, which differ significantly in their chemical environments and consequently in their catalytic performances in reactions. Herein, we report that Pt single atoms anchored at the edges of 2D MoS 2 nanosheets deliver dramatically high activity for CO 2 hydrogenation to CO, in contrast to Pt single atoms as well as their aggregations of 2D-rafts on the in-plane MoS 2 showing inferior activity. By a combination of experimental and theoretical studies, it was found that the activation of CO 2 was significantly facilitated on the Pt single atoms with the synergetic effect of its neighboring Mo at the edges, which readily dissociates into gaseous CO with a low energy barrier. Pt, which is isolated by the S-coordinated surroundings on the in-planes, is inert toward CO 2 adsorption and activation, thus leading to poor activity. This research reveals the close association between the catalytic performance of SACs with their chemical environments, and provides insights into the mechanism modulated by the synergetic effect between single-atom active sites and the support.