Theoretical investigations on novel SiC5 siligraphene as gas sensor for air pollutants

The graphene-based gas sensors are limited by the weak physisorption to gas molecules, and the doping of silicon is an effective way to enhance its sensitivity. By density functional investigations, we reported a novel SiC5 siligraphene (g-SiC5) with great potential in detecting and sensing some specific air pollutants. The g-SiC5 is semimetallic as graphene is, possessing good structural and thermal stability. By comparing the adsorption performance of 12 common gas molecules, we have revealed that the nucleophilic gas molecules could form stable chemisorption with g-SiC5. Among the 12 gas molecules, NO, HCHO and SO2 exhibit moderate adsorption energies in the range of 0.4-0.6 eV when chemisorb on g-SiC5 and would open up a considerable band gap due to the orbital hybridization, thus changing the conductivity of g-SiC5 and making the sensing feasible. The further comparative research demonstrates that the g-SiC5 is superior to Si-doped graphene and other siligraphenes in gas sensing, enabling g-SiC5 to be a promising material as gas sensor for detecting NO, HCHO or SO2 from air mixture.

The g-SiC5 is semimetallic and exhibits good selectivity and sensitivity for air pollutants due to the band gap opening caused by chemisorption, making it promising in gas sensing.168