Influence of preparation technique and iron doping on the structure and reactivity of mixed Fe-Ti-O nanocomposites

Mixed Fe–Ti–O nanocomposites in different compositions were prepared by a wet impregnation technique and compared with the bulk mixed oxide of the same surface composition obtained using the co-precipitation technique. The influence of the preparation method and the iron doping on the structure and reactivity of the mixed oxide were studied by means of various experimental techniques. X-ray photoelectron spectroscopy results indicated a reduction phenomenon at the interface between titania (the support) and iron oxide (the supported) whereas this behaviour was not observed for the bulk mixed oxide. The presence of iron oxide on the surface of titania reduces the hydroxylation. The reactivity with respect to methanol was investigated and the reactivity of titania was found to be increased by the presence of iron oxide on its surface. In particular, the supported sample with a low iron content oxidizes methanol to carbon dioxide at rather low temperatures, which could not be observed for the bulk mixed oxide of the same surface composition. The structures of the supported and bulk mixed oxide samples prepared by the wet impregnation and co-precipitation methods were similar to each other. The structure resembled that of TiO2 (rutile) and the iron doping does not significantly influence the local environment.