Ambient Carbon Dioxide Capture by Boron-Rich Boron Nitride Nanotube

Abstract

Carbon dioxides (CO2) emitted from large-scale coal-fired power stations or industrial manufacturing plants have to be properly captured to minimize environmental side effects. From results of ab initio calculations using plane waves [PAW-PBE] and localized atomic orbitals [ONIOM(wB97X-D/6-31G*:AM1)], we report strong CO2 adsorption on boron antisite (BN) in boron-rich boron nitride nanotube (BNNT). We have identified two adsorption states: (1) A linear CO2 molecule is physically adsorbed on the BN, showing electron donation from the CO2 lone-pair states to the BN double-acceptor state, and (2) the physisorbed CO2 undergoes a carboxylate-like structural distortion and CO π-bond breaking due to electron back-donation from BN to CO2. The CO2 chemisorption energy on BN is almost independent of tube diameter and, more importantly, higher than the standard free energy of gaseous CO2 at room temperature. This implies that boron-rich BNNT could capture CO2 effectively at ambient conditions