DFT investigation of gas sensing characteristics of Au-doped vanadium dioxide

Joy R, Han Z, Xu K, et al. DFT investigation of gas sensing characteristics of Au-doped vanadium dioxide[J]. Physics Letters A, 2020, 384(32): 126823.

Abstract

Vanadium dioxide compounds are affordable and effective materials with large potential in gas sensing applications. However, it is still very challenging for available experiments to provide an in-depth understanding of sensing mechanism of VO₂ -based materials. In this work, density functional theory and molecular dynamics are applied to explore adsorption and diffusion of H₂ , CO₂ , CO and CH₄ gases molecules in Au-VO₂ . Based on calculated adsorption energy, change transfer, charge density difference and density of state, a strong sensing characteristics of Au-VO₂ toward CH 4 gas is concluded, which is consistent with experimental conclusions. It is also inferred that H₂ , CO and CO₂ relate physical adsorption, and CH₄ corresponds to a chemical adsorption. The diffusion of CH₄ in Au-VO₂ is more difficult than the other gases due to the chemical adsorption of CH ₄.