fulltext.study @t Gmail

Effect of nickel precursor and the copper addition on the surface properties of Ni/KL-supported catalysts for selective hydrogenation of citral

Paper ID Volume ID Publish Year Pages File Format Full-Text
43491 45972 2008 10 PDF Available
Title
Effect of nickel precursor and the copper addition on the surface properties of Ni/KL-supported catalysts for selective hydrogenation of citral
Abstract

Effect of the Ni precursor and of the copper addition on the properties of Ni/KL-supported catalysts was studied by TPR, H2 chemisorption, N2 adsorption, CO-FTIR and CO adsorption microcalorimetry. Characterization measurements of catalysts prepared from nickel (II) nitrate hexahydrate, nickel (II) acetylacetonate and nickel (II) phthalocyanine, respectively, show different nickel species distribution in the zeolite, with electron rich metal particles inside the lattice. For NiCu/KL bimetallic catalysts, combined studies by CO-FTIR and by CO adsorption microcalorimetry, together with the TPR results, provide evidence of formation of bimetallic nanoparticles with alloy type structure. The contribution of this species to the surface composition of the catalysts depends on the respective Ni/Cu atomic ratio. Encapsulation of part of the metal components in the zeolite channels and formation of segregated copper particles were also found. Results in the hydrogenation of citral at 323 K in the liquid phase evidence a positive relationship of the catalytic activity with the population of electron rich metal species on the monometallic catalysts. Copper inhibits the hydrogenation activity of nickel and modifies the structure of the exposed nickel surface, which affects the stability of the catalysts and the selectivity for the competitive hydrogenation of conjugated CC and CO bonds of the citral molecule.

Graphical abstractEffects of the metal precursor and of the copper addition in Ni/KL catalysts were analyzed. Both variables affect the nature and location of the metal species formed, as evidenced by the BET, TPR, FTIR-CO and microcalorimetry results, which results in a significant modification of the catalytic performances in the hydrogenation of citral in the liquid phase. Copper inhibits the initial activity of nickel catalysts but improve their stability and modifies the selectivity toward the reaction products.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
KL-zeolite; Ni catalysts; NiCu catalysts; Surface alloy; CO microcalorimetry; FTIR spectroscopy; Citral hydrogenation
First Page Preview
Effect of nickel precursor and the copper addition on the surface properties of Ni/KL-supported catalysts for selective hydrogenation of citral
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 348, Issue 2, 15 October 2008, Pages 241–250
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