The first-principles study of small molecule adsorption on SiO ₂

Based on first-principles calculations within the framework of density functional theory (DFT), the adsorption energies of small molecular compounds CO, HCN, and H2O on SiO2 were calculated. In addition, the band structure, density of states (DOS), and differential charge density during the adsorption process were analyzed. The results show that SiO2 exhibits the strongest adsorption energy toward H2O and the weakest toward CO. After adsorption, the energy bands near the Fermi level become denser compared to those before adsorption, and the hybridisation between the density of states is significantly enhanced. This indicates that the electron transition capability is improved, confirming that there exists a certain degree of adsorption interaction between SiO2 and the small molecular compounds.