Stable, while Still Active? A DFT Study of Cu, Ag, and Au Single Atoms at the C 3 N 4 /TiO 2 Interface

Hybrid DFT calculations are employed to compare the adsorption and stabilization of Cu, Ag, and Au atoms on graphitic C N and on the heterojunction formed by g- C N and TiO . While Cu and Ag can be strongly chemisorbed in form of cations on g- C N , Au is only weakly physisorbed. On g- C N /TiO , all coinage metal adatoms can be strongly chemisorbed, but, while Cu and Ag forms cations, Au form an Au species. Ab Initio Molecular Dynamics simulations confirm that the metal adatoms on g-C N are highly mobile at room temperature, while they remain confined in the interfacial spacing between C N and TiO on the heterojunction, being both stably bound and reachable for the reactants in a catalytic cycle. Doping g- C N /TiO with metal single atoms permits thus to generate catalytic systems with tunable charge and chemical properties and improved stability with respect to bare C N . Moreover, the changes in the electronic structure of g- C N /TiO induced by the presence of the metal single atoms are beneficial also for photocatalytic applications.