Li Yanli, Fang Zhongpu, Zhou Hegen, Li Yi, Wang Bin, Huang Shuping, Lin Wei, Chen Wen-Kai, Zhang Yongfan
State Key Laboratory of Photocatalysis on Energy and Environment, College of Chemistry, Fuzhou University, Fuzhou, Fujian 350116, China.
College of Chemical and Biological Engineering, Yichun University, Yichun, Jiangxi 336000, China.
ACS Omega. 2021 Oct 6;6(41):27259-27270. doi: 10.1021/acsomega.1c04040. eCollection 2021 Oct 19.
The adsorption behaviors of CO at the Cu /TiC(001) interfaces ( = 1-8) have been investigated using the density functional theory method. Our results reveal that the introduction of copper clusters on a TiC surface can significantly improve the thermodynamic stability of CO chemisorption. However, the most stable adsorption site is sensitive to the size and morphology of Cu particles. The interfacial configuration is the most stable structure for copper clusters with small ( ≤ 2) and large ( ≥ 8) sizes, in which both Cu particles and TiC support are involved in CO activation. In such a case, the synergistic behavior is associated with the ligand effect introduced by directly forming adsorption bonds with CO. For those Cu clusters with a medium size ( = 3-7), the configuration where CO adsorbs solely on the exposed hollow site constructed by Cu atoms at the interface shows the best stability, and the charger transfer becomes the primary origin of the synergistic effect in promoting CO activation. Since the most obvious deformation of CO is observed for the TiC(001)-surface-supported Cu and Cu particles, copper clusters with specific sizes of = 4 and 7 exhibit the best ability for CO activation. Furthermore, the kinetic barriers for CO dissociation on Cu- and Cu-supported TiC surfaces are determined. The findings obtained in this work provide useful insights into optimizing the Cu/TiC interface with high catalytic activation of CO by precisely controlling the size and dispersion of copper particles.
利用密度泛函理论方法研究了CO在Cu /TiC(001)界面（ = 1 - 8）的吸附行为。我们的结果表明，在TiC表面引入铜簇可以显著提高CO化学吸附的热力学稳定性。然而，最稳定的吸附位点对Cu颗粒的尺寸和形态敏感。对于尺寸较小（ ≤ 2）和较大（ ≥ 8）的铜簇，界面构型是最稳定的结构，其中Cu颗粒和TiC载体都参与了CO的活化。在这种情况下，协同行为与通过直接与CO形成吸附键引入的配体效应有关。对于那些中等尺寸（ = 3 - 7）的Cu簇，CO仅吸附在界面处由Cu原子构成的暴露空心位点上的构型显示出最佳稳定性，电荷转移成为促进CO活化的协同效应的主要来源。由于在TiC(001)表面支撑的Cu和Cu颗粒上观察到CO最明显的变形，尺寸为 = 4和7的特定铜簇表现出最佳的CO活化能力。此外，还确定了CO在Cu和Cu支撑的TiC表面解离的动力学势垒。这项工作中获得的研究结果为通过精确控制铜颗粒的尺寸和分散度来优化具有高CO催化活化能力的Cu/TiC界面提供了有用的见解。
