团簇Ni_3B_2的成键性质和催化性能

Bonding and catalysis properties of cluster Ni_3B_2

为分析团簇Ni_3B_2的成键性质及催化性能,基于DFT理论,对优化后的8种团簇构型的电子结构和轨道杂化进行系统研究。通过对态密度图的分析,结果发现:团簇Ni_3B_2的三重态构型中,Ni-B键是由s-p-d-s轨道杂化形成的,单重态构型中,Ni-B键是由s-p-d轨道杂化形成的,因此三重态具有更好的稳定性;此外,B-B之间在空间距离较近时,以p-p的形式成键,在空间距离较远时不成键。相较于三重态,单重态构型Fermi能级两侧的峰距离更近,能隙差更低,即单重态构型催化性能优于三重态。

In order to analyze the bonding property of cluster Ni3B2 and its relationship with catalytic performance,based on DFT theory,the electronic structure and orbital hybridization of eight types of Ni3B2 clusters were studied systematically. The results show that in the triplet state configuration of the cluster Ni3B2 the Ni-B bond is formed by the s-p-d-s orbital hybridization,whereas in singlet state configuration the Ni-B bond is formed by the s-p-d orbital hybridization. Therefore,so the triplet state configuration has better stability. In addition,when the spacial distance of B-B is short enough,they form p-p bond,but otherwise no bonding is formed. Compared with the triplet state configuration,the singlet state configuration has a shorter peak distance between the two sides of Fermi level and a lower extent of energy gap. Thus,the singlet state configuration possesses better catalytic property than the triplet state configuration.