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Modified Pd catalysts for the selective hydrogenation of acetylene

Paper ID Volume ID Publish Year Pages File Format Full-Text
55495 47056 2012 15 PDF Available
Title
Modified Pd catalysts for the selective hydrogenation of acetylene
Abstract

This article reviews our previous studies to develop high performance catalysts for acetylene hydrogenation. Ethylene selectivity of Pd catalysts in acetylene hydrogenation was improved by adding Si, metal oxides showing SMSI behavior, and either Ag or Cu as promoters. The promoter effect was further enhanced by maximizing the interactions between Pd and added promoters. Chemical vapor deposition was used for the addition of Si, high-temperature reduction for the SMSI metal oxides, and a surface redox (SR) for Ag and Cu. Si modified the Pd surface geometrically, SMSI metal oxides modified Pd both electronically and geometrically, and Ag modified Pd largely electronically. Cu added by SR modified Pd electronically to a small extent, but preferentially decorated the low-coordination sites of Pd such that the ethylene selectivity of the optimum catalyst was significantly promoted from that of Pd, while its activity remained comparable to that of Pd. The sensitivity of ethylene selectivity to the surface structure of Pd was demonstrated using model catalysts containing uniform-sized Pd particles in either cubic or spherical shapes. The three stage deactivation of the Pd catalyst and the self-regenerative behavior in early stages of deactivation were also investigated.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (134 K)Download as PowerPoint slideHighlights► Si, TiO2, Ag and Cu promoters were selectively deposited onto Pd. ► The surface of Pd was modified geometrically and electronically by added promoters. ► Added promoters improved the ethylene selectivity and lifetime of Pd in acetylene hydrogenation.

Keywords
Acetylene hydrogenation; Si; SMSI; Cu; Selective deposition; Structure sensitivity
First Page Preview
Modified Pd catalysts for the selective hydrogenation of acetylene
Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 185, Issue 1, 20 May 2012, Pages 2–16
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis