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

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.