中文摘要：

在光催化CO2的反应体系中,CO2的吸附活化是一个关键步骤;不同的活化方式和CO2的活化态决定了其反应路线和最终产物.以金属-石墨烯体系为研究对象,采用密度泛函理论方法,结合局域密度近似（LDA）和PWC泛函,计算该体系在CO2吸附前后的几何结构、能量、电荷分布和态密度等的变化.结果表明：电子从金属-石墨烯体系转移到CO2,使CO2带负电并活化;其中Cu-G体系对CO2的活化效果最好,C—O键长分别增加6和14 pm,O—C—O键角减小为122°;金属原子簇和石墨烯的第一电离能和电子亲和势对电子的转移起决定性作用,金属原子簇电子亲和势比石墨烯第一电离能越大,电荷越易从石墨烯转移到金属原子簇.

英文摘要：

Metal-graphene system was taken as the research object. Density functional theory （DFT）, combined with local density approximation （LDA） and PWC functional, was employed to study the changes in the geometry structure, energy, charge distribution and density of states （DOS） of the systems before and after absorption of CO2 on them. The results show that the electrons are transferred from the M-graphene system to CO2, which is eventually activated by negative charge. The Cu-G system is most effective to activate CO2 in these three complexes. The bond length of CO2 increases by 6 and 14 pm, respectively, and the bond angle of O--C-O decreases to 122°. Furthermore, the first ionization energy and electron affinity of metal clusters and graphene play a decisive role in the electron transfer. Compared with the first ionization energy of graphene, the larger the electron affinity of metal clusters, the more the electrons transferred from graphene to metal cluster.