Kinetics of Hydrogen Adsorption and Desorption on Silica-Supported Pt, Rh, and Ru Catalysts Studied by Solid State 1H NMR

• Published in: Langmuir Vol. 18; no. 10; pp. 4005 - 4009
• Main Authors: Savargaonkar, N, Uner, D, Pruski, M, King, T. S
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14.05.2002
• Subjects: 08 HYDROGEN; ADSORPTION; CATALYSTS; DESORPTION; HYDROGEN; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; KINETICS
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la0157263

The kinetics of adsorption and desorption of hydrogen on the multifaceted surfaces of silica-supported Pt, Rh, and Ru catalysts were studied by means of solid state 1H NMR. Experiments with selective inversion of 1H magnetization and the formalism developed by Engelke et al. [J. Chem. Phys. 1994, 101 (9), 7262] were used to extract the adsorption and desorption rate constants and the apparent sticking coefficient. The sticking coefficients of hydrogen measured at 333 K at a surface coverage of 0.4 over 5% Pt/SiO2, 4% Ru/SiO2, and 3% Rh/SiO2 were determined to be 0.014, 0.12, and 0.52, respectively. The corresponding activation energies for desorption were 66, 43, and 79 kJ/mol, respectively.