Confined Catalysis in the g-CN/Pt(111) Interface: Feasible Molecule Intercalation, Tunable Molecule-Metal Interaction, and Enhanced Reaction Activity of CO Oxidation.

The deposition of a two-dimensional (2D) atomic nanosheet on a metal surface has been considered as a new route for tuning the molecule-metal interaction and surface reactivity in terms of the confinement effect. In this work, we use first-principles calculations to systematically explore a novel nanospace constructed by placing a 2D graphitic carbon nitride (g-CN) nanosheet over a Pt(111) surface. The confined catalytic activity in this nanospace is investigated using CO oxidation as a model reaction. With the inherent triangular pores in the g-CN overlayer being taken advantage of, molecules such as CO and O can diffuse to adsorb on the Pt(111) surface underneath the g-CN overlayer. Moreover, the mechanism of intercalation is also elucidated, and the results reveal that the energy barrier depends mainly on the properties of the molecule and the channel. Importantly, the molecule-catalyst interaction can be tuned by the g-CN overlayer, considerably reducing the adsorption energy of CO on Pt(111) and leading to enhanced reactivity in CO oxidation. This work will provide important insight for constructing a promising nanoreactor in which the following is observed: The molecule intercalation is facile; the molecule-metal interaction is efficiently tuned; the metal-catalyzed reaction is promoted.