Syngas Conversion on the Different Cu Surfaces: The Relationship of the Coordination Number of Cu Active Sites with the Activity and Selectivity of Key Intermediate CHₓ Production
2021
Zhao, Wantong | Ma, Lixuan | Wang, Baojun | Ling, Lixia | Zhang, Riguang
Aiming at exploring the relationship of the Cu generalized coordination number (GCN) with the activity and selectivity of CHₓ (x = 1–3) and CH₃OH from syngas on the Cu catalyst, DFT calculations and microkinetic modeling were used to clarify the mechanism of syngas conversion on different Cu surfaces with the GCNs of 4, 4.7, 5.5, 6.5, and 7.5, respectively. The results show that the GCNs of Cu active sites impact the optimal path of CHₓ (x = 1–3) and CH₃OH production, change the existing form of primary CHₓ monomers, and alter the corresponding selectivity and yield. Among these Cu catalysts, the 4.7-GCN of Cu active sites exhibits the highest activity toward the production of primary CH₂ monomers and CH₃OH; however, the activity of CH₃OH production is higher than that of CH₂, leading to a low CH₂ selectivity. Both 5.5-GCN and 6.5-GCN of Cu active sites exhibit moderate activity of CH₂ production and significantly low activity of CH₃OH production; thus, the 5.5-GCN and 6.5-GCN of Cu active sites present the highest selectivity toward primary CH₂ monomers and effectively inhibit CH₃OH production. This study offers valuable clues for the design of other metal catalysts with excellent catalytic performance toward CHₓ (x = 1–3) production by adjusting the GCNs of active sites.
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