Synthesis of high-temperature titania-alumina supports

Catalyst support materials based upon composite metal oxides often incorporate the beneficial aspects of the constituents. For the case of TiO2-Al2O3 composites, however, it has proven difficult to retain a high anatase content and surface area at temperatures of 900 degrees C and above. This work reports a sol-gel synthesis method that solves these problems. The mixed oxide incorporates 100% anatase regardless of composition and at a Ti: Al- 0.4: 0.6 weight ratio has a surface area 74 m(2)/g. Both properties are stable after annealing up to total times of 34 h at 900 degrees C. Experiments with supported Pd show that metal dispersion on the mixed oxide is observed roughly twice that of a pure Al2O3 support. The action of acetic acid in the preparation mixture during sol formation and calcination, augmented by solid solution formation between TiO2 and Al2O3 during calcinations, seems to account for these results.