Dynamically confined single-atom catalytic sites within a porous heterobilayer for CO oxidation via electronic antenna effects

Suppression of clustering of single-atom catalysts during chemical reaction is a long-standing challenge in heterogeneous catalysis, largely due to the prevailing design scheme that the catalytic atoms are anchored onto the supporting surfaces. Here we use first-principles approaches to establish a different design principle, where the single-atom catalytic centers are dynamically sandwiched between a porous g-${\mathrm{C}}_{3}{\mathrm{N}}_{4}/{\mathrm{MoS}}_{2}$ heterobilayer as a prototypical system. We show that many of the transition metals can be well stabilized as dispersive single atoms within the porous centers. Moreover, the single atoms migrate out of their sandwiched homes in ${\mathrm{O}}_{2}$ activation and CO oxidation, and successfully return home after the reaction is completed. In such a dynamical process the single atoms function as electronic antennas, facilitating the charge donation to or acceptance from the reactants, while effectively lowering the reaction barriers. These findings are instructive in establishing high-performance single-atom catalysts upon two-dimensional porous materials.