Effect of N2O pretreatment on fresh and regenerated Pd-Ag/α-Al2O3 catalysts during selective hydrogenation of acetylene

Abstract

N 2 O pretreatment has shown to result in enhancement of the performance of fresh commercial Pd-Ag/α-Al 2 O 3 catalyst during selective acetylene hydrogenation. However, it showed no effect for the used and regenerated catalysts probably due to changes int he metal arrangement on the catalyst surface after regeneration.

Unusual Catalytic Performance for Selective Acetylene Hydrogenation over Pd Nanoparticles Fabricated on N,O-containing Organic Groups Modified Silica

“…So far, it is generally recognized that the electronic and morphological properties of the Pd particles play a dominant role in its catalytic performance [8,9]. Based on this account, several strategies for tuning the electronic and/or morphological properties of Pd-based catalyst by incorporating a second metal such as Au, Ag, Cu and alkali metals [7,[10][11][12], decorating Pd particles with Si [13], pre-treatment with oxygen-containing compounds [14,15], modifying the supports with transition-metal oxides [16] or by selectively poisoning active Pd sites with CO [6,17] have been used to improve their selectivity. Although some of these measures are effective to improve the selectivity of ethylene (S E ), to the best of our knowledge, the ethylene selectivity usually decreases with the increase of acetylene conversion, especially at nearly 100% acetylene conversion and the high molar ratio of H 2 /C 2 H 2 .…”

Enhanced Selectivity in the Hydrogenation of Acetylene due to the Addition of a Liquid Phase as a Selective Solvent

“…Different methods have been investigated to suppress ethane formation, which include enhancing the dispersion of palladium, − adding a second metal to form bimetallic catalysts, ,− utilizing the strong metal–support interaction, − and introducing an inhibiting gas such as CO , and NO x . ,− …”