Charge-regulated CO2 capture capacity of metal atom embedded graphyne: A first-principles study

There are increasing concerns about the environmental impact of rising atmospheric carbon dioxide (CO2) concentrations, thus it is necessary to develop new materials and technologies for efficient CO2 capture and conversion. In this work, we investigated CO2 capture on different metal embedded graphynes (M-GYs) under different charge states via density functional theory (DFT) calculations. It was found that the neutral Ti, V, Cr and Mn embedded GYs could effectively capture CO2 molecules, and the adsorption energy of CO2 was dramatically enhanced on negatively charged M-GYs. The process of CO2 capture/release on Fe or Co embedded GY occurs spontaneously once extra electrons are introduced/removed. Therefore, Fe- and Co-GYs are promising materials for reversible efficient CO2 storage. Ti-GY has the largest CO2 adsorption capacity. By comparing the adsorption of CO2 by non-noble metals and noble metals, it is found that non-noble metals are more conducive to large-scale practical application for CO2 capture due to their high sensitivity to CO2 and low cost. This investigation provides valuable information for designing reusable CO2 storage materials.