摘要
采用电荷自洽方法,以嵌入原子簇Zn4O4为模型,使用量子化学的密度泛函理论,研究了二氧化碳在六方ZnO非极化的(101O)面的可能吸附态.计算表明,CO2垂直底物表面吸附,氧原子只能与Zn原子配位,并且吸附能为很弱的1.8 kJ/mol;吸附质分子平行于底物表面时,得到了5种平衡吸附构型,其中采用C-Zn配位和η2-O,O二齿配位时,吸附很弱,经BSSE校正后的吸附能在8.8～6.6 kJ/mol.采用η2-C,O方式分别与O和Zn配位时,吸附能为31.1kK/mol;C原子与表面O配位时计算得到了唯一的一个化学吸附态,吸附能为139.6 kJ/mol,与实验结果一致.
The adsorption of carbon dioxide on a non-polar ZnO(1010) surface was investigated by the density functional theory (DFT) in combination with charge self-consistence technique by using a Zn4O4 cluster em- bedded in an electrostatic field represented by 136 point charges at the crystal ZnO lattice positions. For the CO2 molecular axis normal to the surface, the O atom can only coordinate to the Zn2+ cation and has a very weak binding energy of 1.8 kJ穖ol-1. When the initial molecular axis is parallel to the surface, the five equilibrium geometries were obtained and four of them have lower binding energies varying from 8.8 to 31.1 kJ穖ol-1 after the inclusion of BSSE correction. The unidentate structure of a carbon atom interacting with a lattice oxygen atom leading to form carbonate has the highest binding energy of 139.6 kJ穖ol-1 which is compatible with the available experimental value.
基金
国家自然科学基金(20273013)
福建省自然科学重大项目(2002F010)
福建省青年科技人才创新基金(2001J018)
福建省教育厅(JA03020)和福州大学科技发展基金资助项目
