Effect of consecutive and alternative oxidation and reduction treatments on the interactions between titania (anatase and rutile) and copper

• Published in: Journal of catalysis 1988-09, Vol.113 (1), p.120-128
• Main Authors: del Arco, Margarita, Caballero, Alfonso, Malet, Pilar, Rives, Vicente
• 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(88)90242-4

Titania (anatase and rutile)-supported copper systems have been prepared by a conventional impregnation technique (2.5% Cu Ti atomic ratio). The effect of consecutive oxidation/reduction/ oxidation and reduction/oxidation treatments at 770 K on the final materials has been studied by X-ray diffraction, transmission electron microscopy, temperature-programmed reduction, and visible-ultraviolet (diffuse reflectance) spectroscopy, as well as assessment of the texture of the solids by nitrogen adsorption at 77 K. Clustered CuO, detected by XRD, is formed on anatase, together with dispersed Cu 2+ species, that are dominant on rutile. On this support, migration of copper species into the bulk of the support crystallites takes place, leading to unreactive copper species, and so, hydrogen consumption during reduction is lower in rutile-supported systems than the expected value to reduce all Cu 2+ species to the metallic state.