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, N-2 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. H-2-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.