The study of adsorption behavior of small molecules on stanene: A search of superior gas sensors

Motivated by the outstanding properties of stanene which is a zero semiconductor with buckled honeycomb structure, we investigate the adsorption behavior of CO, CO2, SO2, and H2S molecule on stanene sheet using the first principles calculations. This study focuses primarily on the energetics, charge transfer, and work function. We determine the optimal adsorption site of small molecule on stanene sheet and the styles of molecule doping, discussing the interaction mechanism between molecule and stanene. The results show that CO, CO2, and H2S molecule are physisorbed on stanene via van der Waals interaction, whereas SO2 molecule are chemisorbed on stanene via strong covalent bond. SO2 adsorption on stanene shows strong hole doping in stanene. The results indicate that the sensing performance of stanene is superior to other 2D materials such as silicene and germanene. It is found that CO, CO2, SO2 molecule act as charge acceptors, whereas H2S molecule serve as charge donors. The nontrivial sensitivity and selectivity of stanene presents that it has a potential application in the field of gas sensors and high performance catalyst.