1 Wide-Pore Zirconia-Titania Mixed Oxides Prepared by Solvothermal Method María C. Barrera 1 , Margarita Viniegra 1 , José Escobar 2 and José A. De Los Reyes 3 1, 3 Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco #186, Col. Vicentina, C. P. 09340. 2 Instituto Mexicano del Petróleo. Introduction The ZrO 2 -TiO 2 system has recently attracted attention as hydrotreating catalyst support [1]. Nevertheless, its low porosity and small pore diameter (3-4 nm) constitute important drawbacks that limits its potential practical applications [2]. Solvothermal treatments during sol-gel processing could contribute to improve the textural properties of mixed oxides [3]. At our best knowledge, the application of that technique to produce wide-pore ZrO 2 -TiO 2 has not yet been reported. Hereby, we describe a low-temperature sol-gel method including solvothermal treatment intended to obtain zirconia-titania systems of tailor-made large pores. Experimental Zr propoxide and Ti isopropoxide were diluted in isopropanol (ROH) to obtain oxides in a 30/70 ZrO 2 /TiO 2 molar ratio as previous studies [4] showed that the surface area (S g ) of this binary system is maximized at this composition. A H 2 O+HNO 3 mixture was drop-wise added to the alkoxides solution kept under vigorous stirring at ~273 K (T s ). The ROH/alk., H 2 O/alk., and HNO 3 /alk. molar ratios used were 65, 20 and 0.05, respectively. After alkoxide hydrolysis the obtained alcogel was subjected to one of the following procedures: aging in the mother liquor or solvothermal treatment (samples ZT and ZTS, respectively). The former was carried out at T s (24 h) with subsequent vacuum drying at room temperature until total solvent elimination. Then, the sample was oven-dried at 393 K (2 h) and finally calcined at T c =573-973 K (4 h) under static air atmosphere. The solvo-treated solids were obtained by transferring the alcogel to a stainless steel hermetic autoclave. The temperature was raised to 353 (L) or 513 K (H) and the sample was maintained under autogenic pressure (1 or 4 days). Posterior processing comprised vacuum drying, oven drying and calcination following the aforementioned procedures. The solids obtained were studied by N 2 physisorption (Autosorb, Quantachrome), XRD (Siemens D-500) and thermal analysis (Netzch STA 409 EP). Results and Discussion The S g of the solid prepared by low-temperature solvothermal method (ZTSL) was higher than that of the solid aged in the mother liquor (ZT) after annealing (Table 1). Conversely, the ZTSH materials showed much lower S g . Although the S g of ZTSL1 (T c =373 K) was larger (1.5 times) than that of the corresponding ZTSL4 sample, both solids showed similar S g after annealing at more severe conditions (773 K). Pore volumes were notably increased in the solvo-treated materials, with the V p