Adsorption of the OH Group on SnO2(110) Oxygen Bridges: A Molecular Dynamics and Density Functional Theory Study

Abstract

The adsorption of water, oxygen, ethanol, and acetic acid onto the SnO2(110) surface was studied using molecular dynamics (MD) simulations. It was found that the atomic arrangement of metal oxide surfaces can play a crucial role in the adsorption and weakening of molecular bonds. The Obridge of this particular metal oxide surface exhibits extraordinary properties that can attract the O–H group of water and ethanol molecules. Moreover, the temperature is also an important factor where it supplies the extra energy required for extreme bond stretching, particularly with the O–H group. However, this will also reduce the performance where the molecules are more likely to diffuse and cannot adsorb onto the surface of SnO2. Other metal oxides (e.g., ZnO and Fe2O3) were also simulated to compare their adsorption behaviors. To verify the MD results, the adsorption and bond stretching behavior of ethanol on the SnO2(110) is compared with the results generated by density functional theory (DFT) simulation. The simulated results are helpful in the determination of influencing factors and understanding the sensing mechanisms of metal oxide materials in gas sensors for practical use.