Structure of catalytic sites on hydrogen-treated copper-containing spinel catalysts

• Published in: Journal of catalysis 1987-10, Vol.107 (2), p.375-392
• Main Authors: Jalowiecki, L., Wrobel, G., Daage, M., Bonnelle, J.P.
• Format: Article
• Language: English
• Subjects: Catalysis; Catalysts: preparations and properties; Catalytic reactions; Chemistry; Exact sciences and technology; General and physical chemistry; General. Nomenclature, chemical documentation, computer chemistry; Theory of reactions, general kinetics; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/0021-9517(87)90303-4

This is a comparative study of the catalytic properties of copper chromites and copper aluminate. The purpose of this study is to identify the nature of the active sites. An analysis of the catalytic properties of various copper-containing catalysts demonstrates the critical importance of the octahedral environment of cuprous ions. Hydride ions, located in anionic vacancies (BMV) shared between the cuprous ion and the chromium or aluminium ion, are the primary active species. The second cation (Cr 3+, Al 3+) is primarily a stabilizer of a defect spinel oxide phase. Since hydrogen reservoir capacity plays an important role in the hydrogenation of dienes, the variation of the occluded hydrogen concentration was studied as a function of the calcination temperature of the oxide precursor as well as a function of the second cation. Taking into account the spinel unit cell, structures of the catalytic sites are proposed. These structures are consistent with the well-known synergism in copper-containing catalysts.