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 TiO ₂-Al ₂O ₂ composites, however, it has proven difficult to retain a high anatase content and surface area at temperatures of 900 °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 °C. Experiments with supported Pd show that metal dispersion on the mixed oxide is observed roughly twice that of a pure Al ₂O ₃ support. The action of acetic acid in the preparation mixture during sol formation and calcination, augmented by solid solution formation between TiO ₂ and Al ₂O ₃ during calcinations, seems to account for these results.