C2H2 selective hydrogenation over the Pd and S-modified Pd catalysts: Unraveling the role of Pd active site spatial scale caused by S atom in adjusting catalytic performance. (1st January 2023)

• Record Type: Journal Article
• Authors: Wu, Yueyue; Wang, Baojun; Fan, Maohong; Ling, Lixia; Zhang, Riguang
• Is Part Of: Fuel. Volume 331:Part 1(2023)
• Publication Date: 2023-01-01
• Subjects: C2H2 selective hydrogenation -- S-modified Pd catalysts -- Spatial scale -- Active site -- Catalytic performance; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2022.125661
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: Pd active site spatial scale can be well adjusted by surface S coverage on Pd catalyst. Catalytic performance of C2 H2 hydrogenation can be regulated by controlling Pd active site spatial scale. The geometric and/or electronic effects caused by S atom play the important role in adjusting catalytic performance. S/Pd-2 × 2 catalyst with surface S coverage of 1/4 ML is screened out to presents excellent catalytic performance. S/Pd-2 × 2 catalyst corresponds to the most appropriate Pd active site spatial scale of 2.691 Å. Abstract: Adjusting the active site spatial scale is an effective way to regulate catalytic performance. In this study, combining DFT calculations with microkinetic modeling, the Pd catalysts and S-modified Pd (S/Pd) catalysts were considered. Here, Pd and S/Pd catalysts were simulated by different supercells and different surface S coverage, respectively. The role of S coverage on Pd surface in adjusting Pd active site spatial scale to regulate catalytic performance of C2 H2 selective hydrogenation was fully investigated. Our results showed that the catalytic performance closely depend on Pd active site spatial scale caused by the coverage of surface S species due to the change of geometric and/or electronic effects caused by S atom. S/Pd-2 × 2 catalyst with S coverage of 1/4 ML and Pd active site spatial scale of 2.691 Å is screened out to simultaneously achieve the best C2 H4 activity and selectivity, as well as the effective prevention of green oil to present excellent catalyst stability, which is attributed to the synergetic geometric and electronic effects caused by S atom. The comparisons between S/Pd and S/Cu catalysts showed that the effect of metal active site spatial scale caused by S atom on catalytic performance still strongly depend on the type of metal catalysts. This study gives a theoretical insight for promoting the target reaction required smaller active site spatial scale and suppressing the side reaction required larger active site spatial scale, in which the active site spatial scale can be reasonably adjusted by changing the coverage of surface S species over the metal catalysts.