High CO2 Sensitivity and Reversibility on Nitrogen-Containing Polymer by Remarkable CO2 Adsorption on Nitrogen Sites

CO2 removal and sensing, especially by amine groups, are necessary to prevent global warming. However, understanding the dynamic mechanism of CO2 capture on nitrogen sites remains challenging. We fabricated a nitrogen-doped polymer and compared the mechanism of CO2 adsorption with that of a similar polymer without nitrogen atoms by evaluating the CO2 adsorption at 243, 273, and 303 K; electrical resistance changes due to CO2 adsorption at 297 K; and molecular dynamics simulations. The CO2 adsorption of the nitrogen-doped polymer was significantly improved owing to the negative partial charges on nitrogen sites. In addition, the electrical response of the nitrogen-doped polymer to CO2 showed adequate reversibility. These results originated from the stronger adsorption of CO2 on nitrogen sites than on ring and vinyl sites. Our findings contribute to the understanding of CO2-nitrogen attraction and will be beneficial for the development of efficient CO2 capture and sensing.