Mechanistic insights into CO 2 activation on pristine, vacancy-containing and doped goldene: a single-atom layer of gold

Goldene, a one-atom-thick gold sheet, is an emerging graphene-like flat 2-dimensional material. In this study, the geometrical and electronic properties, as well as CO2 adsorption characteristics, of the pristine, vacancy-containing, and X-doped (X = Al, B, S, P and N) goldene sheets have been investigated by employing first-principles calculations based on the density functional theory. The distribution of energy levels and interaction between the CO2 molecule and goldene (pristine, partially vacant, and doped) is discussed through the projected density of states (PDOS), electronic band structure (EBS), and Bader charge analysis. We found that CO2 adsorbs physically on pristine goldene (PG) with an adsorption energy of −24.6 kJ mol−1, while the creation of a mono-vacancy (MG), di-vacancy (DG) or tri-vacancy (TG) results in only marginal increases in the binding strength of CO2 with the goldene, and the nature of the interaction remains physisorption. The calculated adsorption energies of CO2 at MG, DG and TG are −25.60, −25.10, and −30.90 kJ mol−1 respectively. Among a range of dopants considered in this work, doping by boron and nitrogen atoms causes goldene to absorb CO2 chemically, with relatively large adsorption energies of −138.9 and −163.7 kJ mol−1 and Bader charge transfers of −1.22 e− and 0.66 e− respectively. Our findings provide an in-depth understanding of the electronic properties of pure, vacancy-containing, and doped goldene, which can aid their potential application in CO2 activation and conversion.