Insight into the Effects of Cu Component and the Promoter on the Selectivity and Activity for Efficient Removal of Acetylene from Ethylene on Cu-Based Catalyst

Abstract

The selective hydrogenation of C2H2 on five types of Cu(0)/Cu­(I), Cu(0), Cu­(I), PdCu(0), and PdCu­(I) catalysts are investigated to illuminate the effects of Cu component and the promoter on the selectivity and activity toward C2H4 formation. The selectivity and activity toward C2H4 formation on five types of catalysts are examined using density functional theory calculations. The results indicate that Cu(0)/Cu­(I) bicomponent catalyst presents higher selectivity but significantly lower activity toward C2H4 formation compared to the individual Cu(0) or Cu­(I) catalysts, suggesting that Cu(0)/Cu­(I) bicomponent catalyst cannot be selected as an ideal catalyst applied to the selective hydrogenation of C2H2, namely, the catalytic activity of Cu catalyst toward C2H4 formation dominates on the single-component rather than the multicomponent. On the other hand, for the promoter Pd-modified Cu(0) or Cu­(I) bimetallic catalysts, PdCu­(I) catalyst presents poor selectivity toward C2H4 formation compared to the individual Cu­(I) catalyst, whereas PdCu(0) catalyst exhibits better selectivity and activity toward C2H4 formation compared to the individual Cu(0) catalyst, indicating that the promoter-modified Cu catalysts should focus on the Cu(0) catalyst rather than the Cu­(I) catalyst. The results not only understand the reaction theories associated with the experimental results but also provide the basic theoretical clues for designing more efficient Cu-based catalysts applied in the selective hydrogenation of C2H2.

C2H2 Selective Hydrogenation to C2H4: Engineering the Surface Structure of Pd-Based Alloy Catalysts to Adjust the Catalytic Performance

“…In this study, when the route of C 2 H 4 desorption is favored, the energy difference between C 2 H 4 desorption and its hydrogenation as the simplest descriptor is employed to quantitatively evaluate C 2 H 4 selectivity. − Meanwhile, the rate of C 2 H 4 formation is calculated to evaluate the activity of C 2 H 4 formation, , which is calculated according to the two-step model , under the typical experimental conditions ( T = 425 K, P = 1 atm; H 2 /C 2 H 2 = 10/1, the partial pressures of C 2 H 4 , H 2 , and C 2 H 2 correspond to 0.89, 0.1, and 0.01 atm, respectively). The details about the definition of activity and selectivity of C 2 H 4 formation are presented in the Supporting Information.…”

Identification of Synergistic Actions between Cu0 and Cu+ Sites in Hydrogenation of Dimethyl Oxalate from Microkinetic Analysis

“…Dissociation of H 2 , DMO, and MG. H atoms derived from H 2 dissociation are essential for DMO hydrogenation. Zhang et al 34 reported that the H 2 dissociation is spontaneous to form the adsorbed H atom on Cu-based catalysts. However, they also reported that an amount of molecularly adsorbed H 2 also exists.…”

C2H2 Selective Hydrogenation over the M@Pd and M@Cu (M = Au, Ag, Cu, and Pd) Core–Shell Nanocluster Catalysts: The Effects of Composition and Nanocluster Size on Catalytic Activity and Selectivity

“…C 2 H 4 selectivity is evaluated by the energy difference between the hydrogenation of C 2 H 4 and the adsorption of C 2 H 4 , which is calculated using eq ,− As shown in eq , Δ G a corresponds to the activation free energy of hydrogenation routes (the C 2 H 4 intermediate or CHCH 3 intermediate route) and G ads corresponds to the activation free energy of the C 2 H 4 adsorption route; when the value of G sel is more positive and larger, which represents that C 2 H 4 more easily undergoes desorption to form gaseous C 2 H 4 instead of ethane formed by C 2 H 4 successive hydrogenation, the catalyst exhibits good C 2 H 4 selectivity.…”