Influence of activated carbon surface chemistry on the activity of Au/AC catalysts in glycerol oxidation

• Published in: Journal of catalysis Vol. 281; no. 1; pp. 119 - 127
• Main Authors: Rodrigues, Elodie G., Pereira, Manuel F.R., Chen, Xiaowei, Delgado, Juan J., Órfão, José J.M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.07.2011; Elsevier; Elsevier BV
• Subjects: Activated carbon; Adsorbents; Catalysis; Catalysts; catalytic activity; Chemistry; Exact sciences and technology; General and physical chemistry; Glycerol; Gold; Mechanism; Oxidation; Surface chemistry; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Glycerol; Gold; Oxidation; Activated carbon; Mechanism; Surface chemistry; Oxygen; Catalytic reaction; Support; Mobility; Transition metal; Selectivity; Density; Supported catalyst; Particle; Heterogeneous catalysis; Chemistry; Acids; Catalyst; Electrons; Functional group
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2011.04.008

The oxygen content of activated carbon surface plays a key role on the activity of Au/AC catalysts for the oxidation of glycerol. Oxygen-free supports promote electron mobility, which enhances the catalytic performance. [Display omitted] ► The sol immobilization method leads to efficient Au/AC catalysts for glycerol oxidation. ► The activated carbon surface chemistry plays a key role in catalysis by gold. ► Activated carbons with high content of acid groups lead to poor performances. ► Basic activated carbons with a high density of free electrons enhance the activity. The main goal of this work is the study of the relationship between the surface chemical characteristics of activated carbon and the performance of the respective gold-supported catalysts in the oxidation of glycerol. For that purpose, a set of modified activated carbons with different levels of oxygenated functional groups on the surface, but with no major differences in their textural parameters, was prepared. A strong effect of the activated carbon surface chemistry on the catalytic activity was observed. Gold particles with similar average sizes resulted in different performances, being the surface oxygenated acid groups particularly prejudicial for the catalytic activity. Basic oxygen-free supports characterized by a high density of free π-electrons lead to more active catalysts; the observation was tentatively explained on the basis of a recent proposed mechanism by considering the capability to promote electron mobility. However, the presence of oxygenated groups on the support does not influence significantly the selectivities.