Li Yueru, Wang Dunyou
College of Physics and Electronics, Shandong Normal University, Jinan, 250014, Shandong, China.
Chemphyschem. 2023 Oct 4;24(19):e202300369. doi: 10.1002/cphc.202300369. Epub 2023 Aug 2.
Ab initio molecular dynamics calculations were performed to study H dissociation mechanisms on Cu and defective graphene-supported Cu clusters. The study reveals that seven types of corresponding dissociation processes are found on the two clusters. The average dissociation energy barriers are 0.51 eV on the Cu cluster and 0.12 eV on the defective graphene-supported Cu cluster, which are lowered by ~19 % and ~81 % compared with the pristine Cu(111) surface, respectively. Furthermore, compared with the pure Cu cluster, the average dissociation energy barrier on the defective graphene-supported Cu cluster is substantially reduced by about 76 %. The preferred dissociation mechanisms on the two clusters are H located at a top-bridge site with the barrier heights of 0.30 eV on the Cu cluster and -0.31 eV on the defective graphene-supported Cu cluster Analysis of the H-Cu bond interactions in the transition states shows that the antibonding-orbital center shifts upward on the defective graphene-supported Cu cluster compared with the one on the Cu cluster, which explains the reduction of the dissociation energy barrier. The average adsorption energy of dissociated H atoms is also greatly enhanced on the defective graphene-supported Cu cluster, about twice that on the Cu cluster.
进行了从头算分子动力学计算，以研究氢在铜以及缺陷石墨烯负载的铜簇上的解离机制。研究表明，在这两种簇上发现了七种相应的解离过程。铜簇上的平均解离能垒为0.51电子伏特，缺陷石墨烯负载的铜簇上为0.12电子伏特，与原始的Cu(111)表面相比，分别降低了约19％和约81％。此外，与纯铜簇相比，缺陷石墨烯负载的铜簇上的平均解离能垒大幅降低了约76％。这两种簇上的优选解离机制是氢位于顶桥位，铜簇上的势垒高度为0.30电子伏特，缺陷石墨烯负载的铜簇上为-0.31电子伏特。对过渡态中氢-铜键相互作用的分析表明，与铜簇相比，缺陷石墨烯负载的铜簇上反键轨道中心向上移动，这解释了解离能垒的降低。在缺陷石墨烯负载的铜簇上，解离氢原子的平均吸附能也大大增强，约为铜簇上的两倍。
