Electron microscopy and 195Pt nuclear magnetic resonance of platinum particles in a zeolite-Y matrix
作者： Y.Y. Tong , J.J. van der Klink , G. Clugnet , A.J. Renouprez , D. Laub
DOI: 10.1016/0039-6028(93)90333-F
关键词:
摘要: Abstract We present the first 195 Pt NMR spectra of platinum particles embedded in a zeolite, and compare them with earlier results on oxide-supported Pt. Slight variations details preparation can make bulk-like signal appear, indicating presence larger than roughly 1.5 nm, that cannot fit into zeolite supercage. TEM observations confirm they are nevertheless inside matrix. Although have nominally clean surfaces, fraction atoms is not metallic environment: this may be caused by interaction framework its counterions, and/or an intrinsic size effect. Hydrogen chemisorption seems to restore character at least partially. This related change lattice constant between hydrogen-covered particles, known occur from EXAFS studies.
harvard.edu
elsevier.com
sci-hub.se 参考文章(19)
M. Boudart, M.G. Samant, R. Ryoo, Atomic and electronic structure and chemical reactivity of metal clusters Ultramicroscopy. ,vol. 20, pp. 125- 133 ,(1986) , 10.1016/0304-3991(86)90178-6
Dieter Exner, Nils Jaeger, Andreas Kleine, Günter Schulz-Ekloff, Reduction–agglomeration model for metal dispersion in platinum-exchanged NaX zeolite Journal of the Chemical Society, Faraday Transactions. ,vol. 84, pp. 4097- 4104 ,(1988) , 10.1039/F19888404097
Dieter Exner, Nils Jaeger, G�nter Schulz-Ekloff, Kontrollierte Variation der Platin-Dispersion in eisenfreien reduzierten PtNaX-Zeolithen Chemie Ingenieur Technik. ,vol. 52, pp. 734- 736 ,(1980) , 10.1002/CITE.330520911
M. Pan, J. M. Cowley, I. Y. Chan, HREM imaging of small Pt clusters dispersed in Y-zeolites Catalysis Letters. ,vol. 5, pp. 1- 11 ,(1990) , 10.1007/BF00772087
J.P Bucher, J Buttet, J.J Van Der Klink, M Graetzel, Electronic properties and local densities of states in clean and hydrogen covered Pt particles Surface Science. ,vol. 214, pp. 347- 357 ,(1989) , 10.1016/0039-6028(89)90175-1
J.P. Bucher, J. Buttet, J.J. van der Klink, M. Graetzel, E. Newson, T.B. Truong, Preparation, characterization and NMR spectra of platinum on alumina catalysts in relation to their activity and stability Journal of Molecular Catalysis. ,vol. 43, pp. 213- 220 ,(1987) , 10.1016/0304-5102(87)87008-6
B. Moraweck, G. Clugnet, A.J. Renouprez, Contraction and relaxation of interatomic distances in small platinum particles from extended X-ray absorption fine structure (EXAFS) spectroscopy Surface Science. ,vol. 81, pp. L631- L634 ,(1979) , 10.1016/0039-6028(79)90125-0
Jean-Pierre Candy, Pierre Fouilloux, Albert J. Renouprez, Hydrogen adsorption on platinum catalysts. Quantitative determination of the various species population Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases. ,vol. 76, pp. 616- 629 ,(1980) , 10.1039/F19807600616
J. P. Bucher, J. J. van der Klink, Electronic properties of small supported Pt particles: NMR study of 195Pt hyperfine parameters. Physical Review B. ,vol. 38, pp. 11038- 11047 ,(1988) , 10.1103/PHYSREVB.38.11038
F LYTLE, Structural genesis of Pt on SiO2: Determination by X-ray absorption spectroscopy☆ Journal of Catalysis. ,vol. 95, pp. 546- 557 ,(1985) , 10.1016/0021-9517(85)90133-2