The Influence of Metal-Support Interactions on the Accurate Determination of Ru Dispersion for Ru/TiO2

• Published in: Journal of catalysis Vol. 149; no. 1; pp. 142 - 148
• Main Authors: Komaya, T., Bell, A.T., Wengsieh, Z., Gronsky, R., Engelke, F., King, T.S., Pruski, M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.09.1994; Elsevier
• Subjects: Catalysis; Catalysts: preparations and properties; Chemistry; Exact sciences and technology; General and physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Chemisorption; Metal support interaction; Ruthenium; Hydrogen; Transition metal; NMR spectrometry; Experimental study; Supported catalyst; Titanium Oxides; Heterogeneous catalysis; Impregnation; Transmission electron microscopy; Platinoid
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1006/jcat.1994.1279

Titania-supported Ru catalysts have been characterized by TEM, 1H NMR, and H2 chemisorption to determine the metal particle size, the fraction of the metal surface available for H2 chemisorption, and the H2 adsorption capacity of the catalyst, as functions of the reduction temperature. TEM micrographs show that as the reduction temperature rises from 573 to 773 K, the average particle size of Ru remains the same but the surface of the particles is covered to an increasing extent by an amorphous layer of titania. Quantitative estimates of the fraction of the Ru particle surface available for H2 chemisorption were obtained by 1H NMR. The NMR spectra also show that a fraction of the adsorbed H2 spills over onto the support and that as a consequence measurements of total H2 chemisorption overestimate the number of Ru sites available for H2 adsorption. The implications of these results for the correct calculation of Ru dispersion and the determination of turnover frequencies for reactions carried out over Ru/TiO2 are discussed.