摘要
采用密度泛函理论广义梯度近似的RPBE方法结合周期性平板模型研究了NO分子分别以N端和O端两种吸附形式在洁净的以及具有氧空穴的CeO_2(110)表面的吸附行为。对比了不同的吸附位及不同覆盖度下的几何构型参数与吸附能。研究结果表明:CeO_2(110)表面O原子上的吸附构型为较稳定的吸附构型,且N端吸附较O端有利;NO在洁净CeO_2(110)表面为物理吸附;当CeO_2(110)表面存在氧空穴时,吸附能明显增大且均大于40 k J·mol^(-1),为化学吸附;覆盖度为0.25 m L时的吸附比较稳定。计算了NO分子吸附前后的态密度以及电荷密度,研究发现:NO分子与底物之间具有相互作用,且整个吸附体系发生了电荷从Ce原子向NO分子的转移,O端吸附时转移的电荷较N端的多。
Adsorption of NO on the CeO2 （110） surface was investigated using RPBE approach of GGA within the framework of density functional theory （DFT） combined with periodic slab model. Two molecular orientations, N- end and O-end, over various adsorption sites, top, hollow, bridge and 0 site of CeO2 （110） surface were considered. Two molecular orientations under different coverage of CeO2 （110） surface also were considered. The optimized results indicated that the N-end adsorption models were more stable than the O-end ones. So N-end adsorption was more favorable than O-end. NO adsorption on a clean CeO2 （110） surface was physisorption, while chemica1 adsorption occurred in the present of surface oxygen vacancy. Adsorption was stable when coverage was set to 0. 25 mL monolayer. Researched on density of states of free NO molecule and adsorbed NO molecule, the results showed that there was an interaction between NO molecule and the substrate . The population analysis indicated that the charges transfered from Ce atoms to NO molecule. The charges transfer of O-end was more than N-end.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2016年第5期618-624,共7页
Journal of the Chinese Society of Rare Earths
基金
内燃机燃烧学国家重点实验室开放基金项目(K2016-05)
江苏省普通高校研究生科研创新计划项目(KYLX_1038)资助
