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Reduction potential, UV–visible absorption edge energy, and oxidation catalysis of niobium-containing H3+xPW12−xNbxO40 Keggin and H6+xP2W18−xNbxO62 Wells-Dawson heteropolyacid catalysts

Paper ID Volume ID Publish Year Pages File Format Full-Text
41481 45890 2011 8 PDF Available
Title
Reduction potential, UV–visible absorption edge energy, and oxidation catalysis of niobium-containing H3+xPW12−xNbxO40 Keggin and H6+xP2W18−xNbxO62 Wells-Dawson heteropolyacid catalysts
Abstract

Niobium-containing H3+xPW12−xNbxO40 (x = 0, 1, 2 and 3) Keggin and H6+xP2W18−xNbxO62 (x = 0, 1, 2 and 3) Wells-Dawson heteropolyacids (HPAs) were prepared in this work to explore their redox properties and oxidation catalysis. Reduction potentials and absorption edge energies of H3+xPW12−xNbxO40 and H6+xP2W18−xNbxO62 HPA catalysts were measured by an electrochemical method and UV–visible spectroscopy, respectively. The trend of reduction potential is well consistent with the trend of absorption edge energy with respect to niobium substitution in both series of H3+xPW12−xNbxO40 and H6+xP2W18−xNbxO62 HPA catalysts. Absorption edge energy of H3+xPW12−xNbxO40 and H6+xP2W18−xNbxO62 HPA catalysts shifted to lower value with increasing reduction potential of the HPA catalysts, regardless of the identity of HPA catalysts; an HPA catalyst with higher reduction potential exhibited lower absorption edge energy. In order to probe oxidation catalysis of H3+xPW12−xNbxO40 and H6+xP2W18−xNbxO62 HPA catalysts, vapor-phase benzyl alcohol oxidation was carried out as a model reaction. Yield for benzaldehyde increased with increasing reduction potential and with decreasing absorption edge energy of H3+xPW12−xNbxO40 and H6+xP2W18−xNbxO62 HPA catalysts.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (179 K)Download as PowerPoint slideResearch highlights▶ H3+xPW12−xNbxO40 and H6+xP2W18−xNbxO62 heteropolyacids were prepared. ▶ Reduction potentials and UV–visible absorption edge energies were measured. ▶ Yield for benzaldehyde increased with increasing reduction potential. ▶ Yield for benzaldehyde increased with decreasing absorption edge energy.

Keywords
Heteropolyacid; Niobium; Reduction potential; Absorption edge energy; Oxidation catalysis
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Reduction potential, UV–visible absorption edge energy, and oxidation catalysis of niobium-containing H3+xPW12−xNbxO40 Keggin and H6+xP2W18−xNbxO62 Wells-Dawson heteropolyacid catalysts
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 394, Issues 1–2, 28 February 2011, Pages 201–208
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