Total oxidation of volatile organic compounds on Au/Ce–Ti–O and Au/Ce–Ti–Zr–O mesoporous catalysts

Cerium–titanium mixed oxides and mesoporous cerium-modified titanium and cerium-modified titanium–zirconium mixed oxides were synthesized in order to obtain active support for gold volatile organic compound (VOC) oxidation catalysts. Ce–Ti mixed oxides were synthesized by sol–gel method. Mesoporous TiO2 and Ti–Zr mixed oxides were prepared through the surfactant templating technique. Gold was loaded on supports by deposition-precipitation method. The catalysts were characterized by thermal analysis, XRD, N2 analysis, TPR, DR/UV–vis and IR. The results evidenced the beneficial role of ceria modifying additive in decreasing the degree of crystallinity of mesoporous support and its particle size. A high degree of synergistic interaction between ceria and mesoporous oxide was observed. H2-TPR revealed that the reducibility of the catalysts is greatly enhanced in the presence of gold. Considering the light off temperature, the activity of Au/mesoporous cerium-modified titanium oxide is particularly interesting for VOC oxidation comparatively to the same catalysts with a classical support. The gold particles would be more dispersed and stable. However, the sample Au/mesoporous cerium-modified titanium–zirconium mixed oxide is less interesting for VOC oxidation, particularly for toluene oxidation whose activity depends essentially on the adsorption of toluene molecule.