Catalysis assisted characterizations of nanosized TiO2-Al2O3 mixtures obtained in molten alkali metal nitrates - Effect of the metal precursor

Mixtures of TiO2 and Al2O3 (0, 5, 10 and 20 mol% Al2O3) were prepared by re action of metal salts with molten alkali metal nitrates. The powders are co nstituted from nanosized anatase crystallites and amorphous alumina. Physic o-chemical characterizations reveal the powders to be homogeneous. Ni-Mo su lphide catalysts were elaborated using these powders as supports and tested in the reaction of hydrogenation of tetralin. The decrease of the intrinsi c catalytic activity per Mo atom, related to the alumina content, is higher than expected for a regular mixing of oxides, suggesting that alumina coat s the anatase particles. On the contrary, it was found that changing the al uminium precursor salt leads to a metastable solid solution which increases significantly the intrinsic activity. (C) 2000 Elsevier Science B.V. All r ights reserved.