In situ high temperature and high pressure exafs studies of Pt/Al2O3 Catalysts. Part II: Carbon removal

• Published in: Catalysis letters Vol. 8; no. 5-6; pp. 297 - 304
• Main Authors: Guyot-Sionnest, N. S., Villain, F., Bazin, D., Dexpert, H., Le Peltier, F., Lynch, J.
• Format: Journal Article
• Language: English
• Published: Springer Verlag 01.09.1991
• Subjects: Chemical Sciences
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/BF00764191

EXAFS has been used to follow in situ the structural evolution of a Pt/A1203 catalystduring removal of carbon by hydrogenation, after reduction and carbon deposition. Afterreduction at 350~ the total hydrogen pressure was raised to 3 atm. and n-heptane wasinjected over the sample. EXAFS measurements at the Pt edge were carried out withsimultaneous on-line EXAFS analysis of the spectra. After observing the rapid formation of acarbon-platinum bond which is unmodified with time, we stopped the heptane flow, raisedthe temperature to 450~ and maintained hydrogen flow at 3 atm. The disappearance of theplatinum-carbon bond during heat treatment in hydrogen was monitored via on-line analysis.No sintering of the metal particles was observed. EXAFS is thus proven to be an efficienttool to study not just structural changes of a catalyst during a hydrocarbon reaction [1], butalso to use it as a technique to study other catalytic phenomena as well.