Density functional theory study on the adsorption properties of SO_2 gas on graphene, N, Ti, and N-Ti doped graphene

摘要

Sulphur dioxide (SO_2) is a corrosive and irritating gas that can cause serious damage to human health and natural environment. Therefore, designing effective gas sensors to detect and remove SO_2 is urgent. The adsorption properties of SO_2 on the graphene, N-doped, Ti-doped, and N-Ti co-doped graphene (N-G, Ti-G and N-Ti-G) are investigated. Our results based on the density functional theory show that SO_2 molecules can stably chemically adsorb on Ti-G and N-Ti-G. The lowest adsorption energy (-2.836 eV) and remarkable charge transfer (0.735 e move from N-Ti-G to SO_2) indicate the N-Ti-G is the optimal adsorbent. Biaxial strain can effectively adjust the adsorption characters and external electric field can enhance the stability of adsorption. Physical adsorption is formed between SO_2 and graphene/N-G due to weak interactions. Our work provides a valuable theoretical guidance for the development of N-Ti-G substrate as promise gas sensor to detection and removal of SO_2.