Temperature-switched MAS NMR: A new method for time-resolved in situ studies of reaction steps in heterogeneous catalysis

✍ Scribed by H. Ernst; D. Freude; T. Mildner

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 567 KB
• Volume: 229
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(94)01045-5

✦ Synopsis

The temperature of zeolite samples containing adsorbed methanol molecules was switched from room temperature to 500-600 K within 30-40 s by means of a laser beam. The catalytic reaction was monitored by 13C MAS NMR and 'H MAS NMR, the latter in steps of one second. A two-dimensional Fourier-transformation of the difference between the time-dependent and the equilibrium state of the system gives a good representation of reaction steps. For the methanol conversion it was found that the primarily formed Q/C4 alkanes are still involved in further reactions, whereas methane is an inert product under these conditions.