Pure TiO2, ZrO2 and TiO2-ZrO2 mixed oxides with various compositions were prepared by the co-precipitation method. Catalysts containing 12wt.% boria were prepared using these oxides and their catalytic performance for vapor-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam was determined.With increasing zirconia content in the mixed oxide, the specific surface area and the temperature of the phase transformation increased; maximum values were obtained for a mixed oxide having a Ti and Zr molar ratio of 1/1. XRD results indicated that TiO2-ZrO2 became amorphous after calcination at 500℃ if neither the content of TiO2 nor that of ZrO2 was less than 25%. The yield of lactam increased with increasing zirconia content in mixed oxide and reached a maximum value for the B2O3/TiO2-ZrO2 (1/1) catalyst.With further increase in zirconia content, the lactam yield decreased; the lowest value was observed for the pure ZrO2-supported catalyst. The acidic property and the pore characteristics of the catalyst were key factors that affected its performance. The influences of the operating parameters on the performance of B2O3/TiO2-ZrO2 (1/1) catalyst were also investigated.

Monte Carlo simulations were used to search for the optimal probability estimator for estimating Weibull parameters with the linear regression method. Compared with commonly used probability estimators, the optimal one obtained gives a more accurate estimation of the Weibull modulus and the same estimation precision of the scale parameter. It is also concluded that the maximum likelihood method results in the highest precision, however, less conservative than the linear regression method.

The TS-1/diatomite catalyst was prepared for the hydroxylation of phenol with H2O2 in the fixed-bed reactor and the effects of pretreatment on the properties of TS-1/diatomite were studied by FT-IR, XRD, UV-vis, ICP-AES, BET surface area and NH3-TPD techniques. It is shown when the catalyst is pretreated by the KAc, NaAc, NH4Ac, NH4Cl or HNO3 aqueous solution, the framework structure of TS-1 is not destroyed and titanium in the framework is not removed. The surface area of catalyst has no obvious change compared with that of the untreated catalyst. But the extra-framework TiO2 can be removed partly, which leads to the slight increase of the crystallinity of catalyst and the decrease of acid concentration on the surface of the TS-1/diatomite catalyst. As a result, the activity, selectivity and utilization of H2O2 for hydroxylation of phenol are improved. After the TS-1/diatomite catalyst is pretreated by the NH3•H2O, Na2CO3 or Na3PO4 solution, its framework silicon is dissolved partly in the base solution and the framework structure of TS-1 is destroyed. While the crystallinity and surface area of catalyst decrease and the concentration of acid sites on the surface of catalyst increased slightly. As a result, the catalytic activity of the TS-1/diatomite catalyst for hydroxylation of phenol descended or deactivated completely.

Direct gas-phase epoxidation of propylene to propylene oxide (PO) by molecular oxygen was studied over the MoO3-modified supportedsilver catalyst. The effect of promoter and support on the performance of the Ag-MoO3 catalyst and their role were investigated by XPS, XRD, SEM, BET surface area, NH3-TPD, CO2-TPD techniques and so on. As the promoter, MoO3 plays a great role of electron- and structure-type bi-functional promoter. Of all the supports studied, ZrO2 is the most suitable one for the Ag-MoO3 catalyst. The presence of support can regulate the size of the Ag-MoO3 particles and the pore radii of catalyst, and decrease the loading of MoO3 from ∼50wt.% in the unsupported Ag-MoO3 catalyst to ∼4wt.% in the Ag-MoO3/ZrO2 catalyst. The properly weak Lewis acidic sites, the larger size of the Ag-MoO3 particles and pore channel on the Ag-MoO3/ZrO2 catalyst are beneficial to improve epoxidation performance of the catalyst. The effect of the reaction temperature and space velocity on the catalytic epoxidation of propylene was also investigated. The low temperature or high space velocity can decrease the deep oxidation of propylene oxide to improve the selectivity to PO. Over the 20%Ag-4%MoO3/ZrO2 catalyst at 400℃, 0.1MPa and space velocity of 7500h−1, the selectivity to PO of 60.3% was achieved with the O2 conversion of 4.8%; under the space velocity of 12 000h−1, the selectivity to PO was 71.5% with 2.5% O2 conversion.

Nanoparticles of the CeO2-ZrO2-La2O3 solid solution were prepared by the W/O microemulsion method. Ceria-zirconia-lanthana (Ce/Zr/La=1/1/0.06,mol) sample calcined at 1000 for 4h has higher surface area (126m2/g) and excellent thermal stability. Its particle size is 5-10nm. The presence of lanthana in the sample can improve obviously the thermal stability of the CeO2-ZrO2 solid solution.