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Investigation of active metal species formation in Pd-promoted sulfated zirconia isomerization catalyst

Paper ID Volume ID Publish Year Pages File Format Full-Text
41781 45900 2010 8 PDF Available
Title
Investigation of active metal species formation in Pd-promoted sulfated zirconia isomerization catalyst
Abstract

The state of palladium in Pd/SO42−–ZrO2 (Pd/SZ) isomerization catalyst was investigated by the temperature-programmed reduction (TPR), chemisorption technique, infrared spectroscopy of adsorbed carbon monoxide (FTIRS), X-ray photoelectron spectroscopy (XPS), diffuse-reflectance UV–vis spectroscopy (UV–vis DRS), and benzene hydrogenation as a test reaction. It has been stated that reduction temperature has a great impact on the metal function of Pd-promoted sulfated zirconia catalyst. Metal centers are formed at about 30–70 °C and characterized by high palladium dispersion and activity in benzene hydrogenation. At temperatures above 200 °C, intensive sulfate decomposition occurs and products of sulfate reduction poison the metal function of the catalyst. According to XPS and FTIRS study, palladium particles in the poisoned samples are only partly oxidized, but the main part is presented by metallic phase without large amount of PdS. Reduction of Pd-containing catalyst at 150 °C (instead of 250 °C) leads to higher conversion and 2,2-dimethylbutane yield in acid-catalyzed reaction of n-hexane isomerization. Higher isomerization activity in this case is provided by prevention of active sulfate species decomposition due to the capability of palladium metallic particles formation at low reduction temperatures.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (46 K)Download as PowerPoint slideResearch highlights▶ Metal sites in Pd/SZ catalyst are formed at about 30–70 °C. ▶ Above 200 °C products of sulfate reduction poison metal function of Pd/SZ. ▶ Lower reduction temperature of Pd/SZ prevents sulfate species decomposition. ▶ Reduction at 150 °C (instead of 250 °C) leads to higher isomerization activity. ▶ Effective Pd/SZ isomerization catalyst with improved metal function is obtained.

Keywords
Palladium; Metal function; Sulfated Zirconia; Isomerization catalyst
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Investigation of active metal species formation in Pd-promoted sulfated zirconia isomerization catalyst
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 387, Issues 1–2, 20 October 2010, Pages 5–12
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us