Confined Catalysis in the g‑C₃N₄/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-C₃N₄) 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-C₃N₄ overlayer being taken advantage of, molecules such as CO and O₂ can diffuse to adsorb on the Pt(111) surface underneath the g-C₃N₄ 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-C₃N₄ 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.