fulltext.study @t Gmail

Effects of noble metal-doping on Cu/ZnO/Al2O3 catalysts for water–gas shift reaction: Catalyst preparation by adopting “memory effect” of hydrotalcite

Paper ID Volume ID Publish Year Pages File Format Full-Text
43636 45980 2008 10 PDF Available
Title
Effects of noble metal-doping on Cu/ZnO/Al2O3 catalysts for water–gas shift reaction: Catalyst preparation by adopting “memory effect” of hydrotalcite
Abstract

Trace amounts of noble metal were doped on Cu/ZnO/Al2O3 catalysts by adopting “memory effect” of hydrotalcite. Ternary Cu/ZnO/Al2O3 (molar ratio Cu/Zn = 1/1, Al content 0–25 mol%) catalysts were prepared by co-precipitation (cp) from metal nitrates; a mixture of hydrotalcite (Cu,Zn)6Al2(OH)16CO3·4H2O, and aurichalcite (Cu,Zn)5(CO3)2(OH)6, was formed at pH 9 with NaOH as the pH controller. Finally the sample, cp-Cu/Zn/Al(45/45/10) containing mainly aurichalcite together with a small amount of hydrotalcite, was selected as the precursor for the noble metal-doping. Noble metal-doping was conducted by dipping the precursor calcined at 300 °C in aqueous solutions of the noble metal nitrates; hydrotalcite was reconstituted by the “memory effect” and simultaneously noble metals were incorporated. The noble metal-doped samples were calcined at 300 °C and tested for the water–gas shift (WGS) reaction. Among the noble metals, Pt was the most effective for stabilizing the catalytic activity although some deactivation due to Cu sintering took place. An intrinsic promoting effect of Pt was clearly observed by evaluating the turnover frequency of the catalyst. Aurichalcite was indispensable for producing active Cu/ZnO sites, whereas a small amount of hydrotalcite was effective for improving the sustainability of the catalyst by the surface modification. It is likely that hydrogen-spillover from trace Pt to active Cu metal not only enhanced the activity via the reduction–oxidation cycle between Cu0 and Cu+ but also stabilized the active Cu metal species against oxidative sintering during the reaction.

Graphical abstractTrace amount of Pt-doped Cu/ZnO/Al2O3 catalyst prepared by adopting “memory effect” of hydrotalcite showed a sustainable activity for the water–gas shift reaction; hydrogen-spillover from Pt to active Cu metal enhanced the stability of active Cu metal species against oxidative sintering.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Water–gas shift reaction; Pt-doped Cu/ZnO/Al2O3 catalyst; Co-precipitation; Aurichalcite; Hydrotalcite; “Memory effect”
First Page Preview
Effects of noble metal-doping on Cu/ZnO/Al2O3 catalysts for water–gas shift reaction: Catalyst preparation by adopting “memory effect” of hydrotalcite
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
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 337, Issue 1, 15 March 2008, Pages 48–57
Authors
, , , , , , ,
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