Biotemplate synthesis of micron braid structure CeO2-TiO2 composite and analysis of its catalytic behavior for CO oxidation

A series of CeO2-TiO2 composite samples with different Ce/Ti molar ratios were prepared by the paper template. Powder X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to confirm a face-centered cubic lattice of CeO2 with Ce/Ti =8:2 or 9:1 and a two phase mixture of anatase titania and face-centered cubic ceria with Ce/Ti = 7:3. The field emission scanning electron microscopy (FESEM) results suggest that the products are micron braid structures consisting of fibers with diameters in a range of 1-6 μm and lengths of several hundred micrometers. N2 absorption-desorption testing shows that the composite at Ce/Ti molar fraction of 8:2 has the largest BET surface area (about 81 m2·g-1). Compared to the pure CeO2 sample, the composites show superior catalytic activity for H2 reduction and CO oxidation. For the micron braid structure CeO2-TiO2 composite (Ce/Ti = 8:2), due to the high surface area and the solid solution with appropriate Ti4+ incorporation, the CO conversion at about 280°C was above 50% and at 400°C was 100%.