Furfural adsorption on the g-C3N4 monolayer: A DFT analysis

Graphitic carbon nitride (g-C3N4) has attracted much attention in recent years as a material for catalytic processes due to its promising structural and physicochemical properties. However, the role played by the g-C3N4 during the catalytic activity is often briefly discussed. Consequently, the mechanism behind these substrate-adsorbate processes involving g-C3N4 still needs to be better understood. This study analyzed furfural (FAL) adsorption on h-g-C3N4 monolayers based on DFT, including Van der Waals (vdW) interactions. To elucidate the role of the h-g-C3N4 in catalytic systems, the adsorption of a FAL molecule was evaluated at high and low coverages. At high coverage, due to proximity effects, FAL molecules interact with neighboring FAL molecules forming a monolayer that lays over the h-g-C3N4 nanosheet. At low coverage, weak interactions govern the FAL-h-g-C3N4 interaction. In both cases, vdW interactions are the main forces that bring stability to the composites. No chemical interactions are observed. The obtained results led us to conclude that in reactions including FAL and h-g-C3N4 nanosheets, the latter will serve as a support structure that favors the adsorbate mobility to reach the reactive centers.