First-Principles Study of Electrocatalytically Reversible CO2 Capture on Graphene-like C3 N.

Developing advanced materials and new technologies for efficient CO2 capture and gas separation can enormously alleviate its impact on global climate change. In this study, we report a comprehensive density functional theory investigation of N2 , CH4 , H2 , and CO2 adsorption on a graphene-like C3 N monolayer. Our calculation results show that the four gas molecules are all physisorbed on the neutral C3 N monolayer. However, the interaction between CO2 and C3 N can be significantly boosted via the strategies of electrochemical methods such as introducing negative charge or applying external electric field to the system. While the adsorption of N2 , CH4 and H2 on C3 N monolayer is slightly influenced with the above strategies. Moreover, CO2 will release spontaneously from C3 N monolayer once the extra charge or electric field is removed from the system. These results demonstrate that the CO2 capture, regeneration and separation on C3 N monolayer can be controllable with the method of switching on/off the charge state or electric field during the adsorption. In addition, as a new synthesized 2D material (PNAS, 2016, 113, 7414-7419), C3 N possesses an extremely narrow band gap of 0.39 eV, which guarantees applying negative charge or electric field to it can be easily realized in experiment by electrochemical methods.