The Structural and Electronic Properties of the Ag₅ Atomic Quantum Cluster Interacting with CO₂, CH₄, and H₂O Molecules

Recent advancements in experimental approaches have made it possible to synthesize silver (Ag₅) atomic quantum clusters (AQCs), which have shown a great potential in photocatalysis. This study employs the generalized gradient approximation (GGA) density functional theory (DFT) to explore the adsorption of CO₂, CH₄, and H₂O molecules on the Ag₅ AQC. Our investigations focus on the structural and electronic properties of the molecules in Ag₅ AQC systems. This involves adsorption energy simulations, charge transfer, charge density difference, and the density of states for the modelled systems. Our simulations suggest that CH₄ and H₂O molecules exhibit higher adsorption energies on the Ag₅ AQC compared to CO₂ molecules. Remarkably, the presence of CH₄ molecule leads to a significant deformation in the Ag₅ AQC structure. The structure reforms from a bipyramidal to trapezoidal shape. This study also reveals that the Ag₅ AQC donates electrons to CO₂ and CH₄ molecules, resulting in an oxidation state. In contrast, gaining charges from H₂O molecules results in a reduced state. We believe the proposed predictions provide valuable insights for future experimental investigations of the interaction behaviour between carbon dioxide, methane, water molecules, and Ag₅ sub-nanometre clusters.