TiO2 supported Pd@Ag as highly selective catalysts for hydrogenation of acetylene in excess ethylene

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 se-lectivity towards ethylene was in the order of Pd-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.

Fabrication of a PdAg mesocrystal catalyst for the partial hydrogenation of acetylene

“…The selectivities at >99.5% conversion, which is a greater challenge and more relevant to the industrial process, were also compared. Although the selectivity toward ethene decreases sharply for both catalysts at such a high conversion, the value over PdAg MCs/HT (70%) is slightly higher than that over PdAg NPs/HT [74,75,78], but the values are lower than those for PdCu catalysts reported by Anderson and co-workers [6]. As for the intrinsic activity, the PdAg MCs/HT catalyst has a TOF of 0.045 s À1 , which is higher than the values for monometallic Pd NPs/HT and PdAg NPs/HT catalysts (Entries 1 and 2).…”

Core–shell nanoparticles: synthesis and applications in catalysis and electrocatalysis

“…[299][300][301] Nanomaterial-catalyzed hydrogenations of alkynes, alkenes, aromatic nitro compounds and ketones have received much interest in the last decade because of their use in the synthesis of important raw materials along with the remarkable effectiveness of nanomaterials in catalyzing such reactions. [308][309][310][311] 4.1.1. Among such processes, catalytic transfer hydrogenation (CTH) reaction is becoming increasing popular because of its wide usage and versatility.…”

Recent advances in selective acetylene hydrogenation using palladium containing catalysts

“…A number of recent studies have looked at the choice of second metal as well as the method of introduction. Han et al [51] reported a novel method for introduction of Ag to Pd/TiO 2 catalysts via sequential photo-deposition. Based on FTIR of adsorbed CO it was thought that this resulted in the preferential deposition of Ag onto a Pd core, as opposed to metal mixing.…”