A first principles study of CO2 adsorption on α-SiO2(001) surfaces

Abstract

In this work, using first principles calculations, an analysis of CO₂ interaction with cleaved and reconstructed α-SiO₂(001) surfaces was performed. We showed that CO₂ could strongly interact with a cleaved surface forming CO3-like configurations. Here, the binding energy per CO₂ molecule depends strongly on CO₂ surface coverage and can reach −2.35 eV. Despite this, even with CO₂ molecules, the cleaved surface has a substantially higher surface energy than that of the reoptimized “dense” surface. This observation is also consistent with molecular dynamics simulations. Because of this, for thermodynamically stable system, the interaction of CO₂ molecules with a α-SiO₂(001) surface should be treated as the physisorption of CO₂ molecules on the reoptimized “dense” surface with the binding energy varying from −0.26 eV for single CO₂ molecule adsorption to −0.32 eV per molecule for monolayer coverage.