丙烯腈在Cu(100)表面化学吸附的密度泛函理论研究  

DFT Study of the Chemisorption of Acrylonitrile on the Cu(100) Surface

作　　者：夏树伟[1] 高林娜[1] 徐香[1] 孙雅丽[1] 夏少武[2] 

机构地区：[1]中国海洋大学化学化工学院,青岛266003 [2]青岛科技大学化学与分子工程学院,青岛266042

出　　处：《化学学报》2006年第1期27-31,共5页Acta Chimica Sinica

基　　金：国家自然科学基金(No.20203011)资助项目.

摘　　要：利用密度泛函方法,模拟金属铜原子簇Cu14(9,4,1)的(100)表面,对丙烯腈(CH2=CHCN)在Cu(100)面上不同吸附位的吸附状况进行了理论研究.结果表明:丙烯腈分子通过端位N原子垂直吸附在金属表面上为弱化学吸附,部分电荷从丙烯腈分子转移至铜金属簇;由N原子的孤对电子与金属铜形成弱σ共价键;顶位是最佳吸附位,吸附能为40.7391kJ?mol-1,N原子与金属表面间的平衡距离为0.2279nm;其次为桥位和穴位,吸附能分别为36.2513和30.2158kJ?mol-1,平衡距离为0.2194和0.2886nm;吸附后C≡N键的强度降低,活化了丙烯腈分子.化学吸附使体系的熵减小,是由于丙烯腈分子的平动和转动因吸附而被限制.The adsorption of acrylonitrile （AN） on the different sites of Cu（100） surface has been studied theoretically by means of model copper cluster Cu14（9,4,1） with density functional theory （DFT）. AN standing up and adsorbed perpendicularly to the surface and bonded to the metal sites via a nitrogen-metal interaction took a weak chemisorption. Such chemisorption led to electron transfer from the AN molecule to the cluster. In the metal complexes of CU14-AN, the σ-bonding via the lone pair electrons on the N atom was observed. Chemisorption on top site was preferred with the adsorption energy of 40.7391 kJ·mol^-1 and the equilibrium N-surface distance of 0.2279 nm, while both bridge and hole sites were less stable than the top one, with their adsorption energies of 36.2513 and 30.2158 kJ·mol^-1, N-surface distances of 0.2194 and 0.2886 nm respectively. AN was activated by the chemisorption, which made the decrease of the strength of C≡N. The major contributions to the entropy decrease came from rotations and translations of AN, since these motions were lost upon chemisorption.

关 键 词：密度泛函:丙烯腈 CU(100) 化学吸附 

分 类 号：O647.311[理学—物理化学]