Low temperature FT-IR studies of NO adsorption on aluminum oxide and supported palladium

✍ Scribed by Dilip K. Paul; Barry W. Smith; Chad D. Marten; Justin Burchett

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 459 KB
• Volume: 167
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/s1381-1169(00)00492-1

✦ Synopsis

Low temperature FT-IR spectroscopy has been utilized to study the adsorption and thermal decomposition of NO on Al 2 O 3 and Al 2 O 3 -supported palladium. At 110 K the nitric oxide adsorbs molecularly and reversibly via H-bonding to isolated surface -OH groups forming the (NO) 2 dimer. The dimer formation was characterized by symmetric and antisymmetric ν(N-O) stretching modes at 1871 and 1761 cm -1 , respectively. However, upon warming the adsorbed (NO) 2 dimer decomposes to form adsorbed nitrous oxide. The reactive species is thus shown to be the adsorbed dimer, which cannot be formed at temperatures greater than 140 K for lack of H-bonding. As the palladium loading is increased, there is a gradual decrease in (NO) 2 dimer formation with an increase in chemisorbed Pd-NO because of adsorption site transfer from Al 2 O 3 to Pd.