posted on 2021-10-06, 23:47authored byYanli Li, Zhongpu Fang, Hegen Zhou, Yi Li, Bin Wang, Shuping Huang, Wei Lin, Wen-Kai Chen, Yongfan Zhang
The adsorption behaviors
of CO2 at the Cun/TiC(001)
interfaces (n = 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 CO2 chemisorption. However, the most stable adsorption site is
sensitive to the size and morphology of Cun particles. The interfacial configuration is the most stable structure
for copper clusters with small (n ≤ 2) and
large (n ≥ 8) sizes, in which both Cu particles
and TiC support are involved in CO2 activation. In such
a case, the synergistic behavior is associated with the ligand effect
introduced by directly forming adsorption bonds with CO2. For those Cun clusters with a medium
size (n = 3–7), the configuration where CO2 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
CO2 activation. Since the most obvious deformation of CO2 is observed for the TiC(001)-surface-supported Cu4 and Cu7 particles, copper clusters with specific sizes
of n = 4 and 7 exhibit the best ability for CO2 activation. Furthermore, the kinetic barriers for CO2 dissociation on Cu4- and Cu7-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 CO2 by precisely controlling the size and
dispersion of copper particles.