fulltext.study @t Gmail

Exposing the synergistic effect between copper and vanadium in AlPO-5 during the selective oxidation of propene

Paper ID Volume ID Publish Year Pages File Format Full-Text
54107 46997 2014 9 PDF Available
Title
Exposing the synergistic effect between copper and vanadium in AlPO-5 during the selective oxidation of propene
Abstract

•We found that having copper and vanadium deposited on AlPO-5 increased the activity of propene oxidation to acrolein.•The synergistic effect was studied using in situ XAS on copper and vanadium K-edge.•The presence of copper on AlPO-5 increased the reducibility of vanadium, compared to the monometallic analogue (V:AlPO-5).•The suggested redox mechanism is a Mars van-Krevelen mechanism in which Cu(I) is the driving force for reduction.

Vanadium and copper were co-deposited into the microporous AlPO-5 to obtain VCu:AlPO-5. The catalytic activity towards selective oxidation of propene with feed gas components C3H6:4 O2 show maximum yield of 3.9% at 400 °C with 5.5% acrolein selectivity. The activity towards acrolein is clearly enhanced in VCu:AlPO-5, when compared to monometallic analogues V:APO-5 and Cu:APO-5. The synergism between vanadium and copper was investigated with in situ XAS at the V and Cu K-edge during cycling in reaction components (C3H6/O2). Vanadium is initially present as pentavalent square pyramidal V(5+) indirectly bonded to copper at 2.9 Å as confirmed by EXAFS. Vanadium was gradually reduced by propene to obtain 30% V(4+) fraction in VCu:AlPO-5, coinciding with rapid reduction of Cu(II) to Cu(I) (60%). Reduction in propene is accompanied by a decrease in the average VO and CuO first shell multiplicities. Interestingly, acrolein is formed over VCu:AlPO-5 in propene only, but the activity decreases with time on stream. After switching to oxygen the activity is diminished and the local vanadium and copper surroundings are restored. Reduction of vanadium was not observed in V:AlPO-5, hence copper promotes the reducibility of vanadium and propene oxidation is activated by the dynamic nanoparticulate CuVOx/Cu(I)V(4 + )Ox − 1 species formed in AlPO-5.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (123 K)Download as PowerPoint slide

Keywords
Vanadium; Microporous materials; Propene oxidation; XANES
First Page Preview
Exposing the synergistic effect between copper and vanadium in AlPO-5 during the selective oxidation of propene
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: Catalysis Today - Volume 229, 15 June 2014, Pages 14–22
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