CO2 activation on metal- and non-metal-doped goldene sheets: A DFT study

Goldene is a novel two-dimensional monolayer (2D) of gold atoms arranged in a hexagonal close-packed crystal lattice. In this study, we have employed density functional theory (DFT) calculations to investigate CO2 activation on doped goldene sheets (G_X, where X represents the dopant). We targeted three distinct categories for the doping process: Alkali metals (AMs = Li, Na, K, and Rb), alkaline earth metals (AEMs = Be, Mg, Ca, and Sr), and non-metals (NMs = C, O, and Se). Our study reveals that Be doping leads to the most robust structure among all considered G_X sheets, with a binding energy (Eb) of −4.73 eV, whereas AEM dopants are found to bind more strongly with goldene compared to AM dopants. No dopant was able to induce a gap between the energy bands, and the goldene preserves its metallic character and flat geometry even after doping. The CO2 molecule adsorbs on AM-doped goldene sheets with a high adsorption energy (Eads) but remains linear after adsorption. However, in the case of AEMs, CO2 chemically adsorbs on the G_Be sheet and becomes activated by bending (136.28°). The presence of NMs (C and O) enhances the chemical activity of goldene towards CO2 conversion.