First-principles study of χ3-borophene for charge-modulated switchable CO2 capture

A first-principles calculation was performed to investigate the switchable CO2 capture on chi(3)-borophene by injecting/removing the extra electrons. The results show that the CO2 adsorption energy on the neutral chi(3)-borophene is 0.150 eV. After extra 2.5 e are injected, the adsorption energy is raised up to 0.802 eV, showing a significant enhancement with the change from the physical adsorption to chemical adsorption. Furthermore, both the CO2 capture and release processes are exothermic reactions involving injecting/removing extra electrons. chi(3)-borophene possesses a metallic electronic structure, which is conducive to the injection of extra electrons. The minimum charge density for CO2 capture on the negatively charged chi(3)-borophene is 1.6 x 10(14) e cm(-2). The CO2 capture capacity of chi(3)-borophene is 4.09 x 10(14) cm(-2). Finally, we study the selectivity of negatively charged chi(3)-borophene. The results show that the negatively-charged chi(3)-borophene possesses a high selectivity for CO2 from its mixtures with CO, CH4, NH3, N-2, H2S, and H-2. chi(3)-borophene is a new promising charge-modulated switchable CO2 capture material with good stability, high CO2 capture capacity, high selectivity, and excellent electrical conductivity.