Layered Double Hydroxides Derived ZnO‐Al₂O₃ Supported Pd‐Ag Catalysts for Selective Hydrogenation of Acetylene

Abstract

ZnO-Al 2 O 3 derived from layered double hydroxides (ZnAl-LDH) was successfully applied for dispersion of Pd-Ag bimetallic catalysts for the selective hydrogenation of acetylene to ethylene and the Pd-Ag/ZnO-Al 2 O 3 catalyst showed the best catalytic performance among the prepared samples. It was found that the catalyst carrier of ZnO-Al 2 O 3 metal-oxides derived form ZnAl-LDH could significantly suppress the over-hydrogenation of acetylene to obtain the relatively higher selectivity of ethylene. The introduction of Ag restricted efficiently the formation of coke because of the oligomerization reaction, which was further evidenced by thermal gravimetric analysis. The selectivity towards ethylene was in the order of Pd-Ag/ZnO-Al 2 O 3 ＞Pd/ZnO-Al 2 O 3 ＞Pd-Ag/Al 2 O 3 ＞Pd/Al 2 O 3 at a high conversion level. As the thermal gravimetric and differential temperature analysis (TG-DTA) revealed, Pd-Ag intermetallic catalyst on the ZnO-Al 2 O 3 support showed less coke formation.

Recent research advances on catalysts for selective hydrogenation of ethyne

“…Since VIII metals such as Pd and Ni are strong in ethyne activation and IB metal-based catalysts are selective for ethylene formation, VIII-IB bimetallic catalysts have been widely constructed to achieve high ethyne conversion and high selectivity towards ethylene simultaneously. Pd-Ag, 20,[101][102][103][104][105][106][107][108][109][110][111][112][113] Pd-Au, 114,115 Pd-Cu, [116][117][118] Ni-Cu, 119 Pt-Cu, 120 Ni-Ag, 121 and Ni-Au (ref. 122) have been developed.…”

Acetylene in Organic Synthesis: Recent Progress and New Uses

“…Withdrawing of electron density from Ti 3+ by Pd enhanced the Pd-support interaction. Using ZnAl instead of TiO 2 significantly improved the selectivity/conversion and also the oligomer selectivity [ 283 ]. Decreased amounts of carbonaceous deposits were observed for PdAg/ZnO-Al 2 O 3 in comparison with Pd/Al 2 O 3 , PdAg/Al 2 O 3 , and Pd/ZnO-Al 2 O 3 ( Figure 20 ).…”

“… Product selectivities ( a ) and C 2 H 4 yields ( b ) for PdAg/ZnAl catalysts, 180 min at 90 °C (reproduced with permission from [ 283 ]. Copyright 2017 WILEY-VCH Verlag GmbH & Co. KGaA).…”

Liquid-Phase Hydrogenation of 1-Phenyl-1-propyne on the Pd1Ag3/Al2O3 Single-Atom Alloy Catalyst: Kinetic Modeling and the Reaction Mechanism

“…In this study the focus was on studying experimentally hydrogenation of a substituted alkyne on a Pd-Ag SAA catalyst and analyzing its kinetics with eventual kinetic modeling. The choice of the system was dictated by the fact that Pd-Ag catalysts are among the most effective industrial systems for the removal of acetylene impurities from ethylene, and that excellent selectivity of PdAg SAA was previously reported in liquidphase [12] and gas-phase alkyne hydrogenation [20,[42][43][44][45][46]. Thus, in hydrogenation of diphenylacetylene excellent (ca.…”