A new bifunctional C3N nanosheet of NO2, SO2 gas sensor and CO2 separation: A first-principles study

Abstract

A new-style two-dimensional C 3 N monolayer, unlike the honeycomb C 3 N monolayer, is proposed as a gas sensor, capture and separation. By using the first-principles method, the adsorption behaviors of gas molecules (NH 3 , H 2 S, SO 2 , CO, CO 2 , NO, NO 2 , CH 4 , HCN, N 2 , H 2 and O 2 ) on the C 3 N monolayer were investigated, and the charge density difference, density of state and Hirshfeld charge of those adsorption systems were also discussed. The results show that the SO 2 and NO 2 are chemisorbed on the C 3 N nanosheet with large adsorption strength, while the other gases are adsorbed by weak physisorption. The analysis of charge density difference and density of state suggests that SO 2 and NO 2 gain much charge from C 3 N sheet, and the hybridizations between C 3 N sheet and SO 2 /NO 2 -p orbitals lead to strong gas-adsorbent interactions. The recovery time of SO 2 and NO 2 is predicted to be 7.47 × 10 −4 s and 15.91 s at room temperature. Additionally, the CO 2 can be captured and separated from the mixtures of CO 2 , NH 3 , H 2 S, CO, CH 4 , H 2 through injecting two electrons into C 3 N sheet. Therefore, the new C 3 N nanosheet can be a promising bifunctional material as SO 2 , NO 2 sensor and CO 2 separation.