科研之友
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摘要
The development of highly efficient sorbent materials for CO, capture under ambient conditions is of great importance for reducing the impact of CO2 on the environment and climate change. In this account, strong CO2 adsorption on a boron antisite (B-N) in boron-rich porous boron nitrides (p-BN) was developed and studied. The results indicated that the material achieved larger adsorption energies of 2.09 eV (201.66 kJ/mol, PBE-D). The electronic structure calculations suggested that the introduction of B-N in p-BN induced defect electronic states in the energy gap region, which strongly impacted the adsorption properties of the material. The bonding between the B-N defect and the CO2 molecule was clarified, and it was found that the electron donation first occurred from CO2 to the B-N double-acceptor state then, followed by electron back-donation from BN to CO, accompanied by the formation of a B-N-C bond. The thermodynamic properties indicated that the adsorption of CO2 on the B-N defect to form anionic CO2 delta- species was spontaneous at temperatures below 350 K. Both the large adsorption energies and the thermodynamic properties ensured that p-BN with a B-N defect could effectively capture CO2 under ambient conditions. Finally, to evaluate the energetic stability, the defect formation energies were estimated. The formation energy of the BN defects was found to strongly depend on the chemical environment, and the selection of different reactants (B or N sources) would achieve the goal of reducing the formation energy. These findings provided a useful guidance for the design and fabrication of a porous BN sorbent for CO2 capture.
- 出版日期2017-5-10
- 单位河北工业大学
