Sulfur dioxide adsorbed on pristine and Au dimer decorated γ-graphyne: A density functional theory study

Abstract

In this work, we investigated the adsorption behaviour of sulfur dioxide on pristine and Au dimer decorated γ-graphyne (γ-GY). From comparing the adsorption energy, electron transfer and band gap, the most energetically adsorption configurations were gained. Then we made a further discussion of charge density difference, electron localization function (ELF), band structure, density of states (DOS) to evaluate the chemical and physical interactions between the SO2 and the γ-GY. The results indicated that the SO2 adsorption on the pristine γ-GY just exhibited van der Waals force with very weak chemical interactions. But SO2 could be adsorbed on Au dimer decorated γ-GY with relatively stronger chemical interactions due to the larger adsorption energy, larger electron transfer, the obvious change of SO2 molecular orbitals and many hybridizations between the Au and the S atom in DOS. Because of the unchanged band gap of Au dimer decorated γ-GY, it is more suitable for Au2-GY to be applied in QCM gas sensor to detect SO2 rather than resistance type gas sensor.