Publications

Ag/TiO2composite nanoparticle catalyst was prepared by photoreduction-deposition method. The morphology of silver particles could be changed by controlling pH value of the solution, and the well-dispersed silver particles were obtained on the surface of TiO2nanoparticles. The photocatalytic activity of Ag/TiO2was measured by using photocatalytic oxidation of aniline as a model reaction, and the effects of Ag loading on the photocatalytic activity were studied. The photocatalytic oxidation of aniline indicated that the photocatalytic activity of TiO2nanoparticles could be greatly improved by depositing appropriate amount of silver on their surface. The morphology of coated silver had a direct effect on the photocatalytic activity of Ag/TiO2catalyst. Well-dispersed Ag particles with a proper loading could improve the photocatalytic oxidation of aniline efficiently.

Titania-supported palladium-copper bimetallic catalysts (Pd-Cu/P25) are prepared by liquid-phase chemical reduction method and then applied in liquid-phase catalytic reduction of nitrite ions (NO2-). Compared with the conventional impregnation method, which usually needs a post-thermal reduction procedure to eliminate the introduced anions, liquid-phase chemical reduction at ambient temperature was proved to inhibit the aggregation of metal active components by means of TEM and DSC analysis in this work, and the catalyst exhibited superior catalytic activity. The conversion of nitrite reached a high level (1 × 10-4mol min-1gcat-1) and is about 14 times than that reported recently. The influences on the conversion of NO2-by support materials and the molar ratio of palladium to copper are also investigated, and further, the reaction mechanisms are discussed according to the characterization results of XPS and in situ FT-IR.

Different metal ion-exchanged ZSM-5 zeolites were investigated, by means of H2-temperature-programmed reduction (H2-TPR) and O2-temperature-programmed desorption (O2-TPD). Pure Cu-ZSM-5 and in-situ synthesized Cu-ZSM-5/cordierite monolithic catalysts were also characterized by H2-TPR in order to compare the oxidation states of copper ions on them. The results show that the Cu-ZSM-5 catalyst has superior oxygen storage capacity than the Co-ZSM-5 and Fe-ZSM-5. The catalyst activity for NO decomposition is closely related to this property. Copper ions are the active sites for the reaction. The addition of Ag and Ce as promoters decreases the temperature of O2desorption, which indicates that adding Ag and Ce favors the O2desorption from the catalyst surface. The state of Cu on the Cu-ZSM-5/cordierite monolithic catalyst is different from that on the pure Cu-ZSM-5. Less Cu+species is found on the monolithic sample but it is more stable than that on the pure Cu-ZSM-5.

The NO decomposition reaction on Cu-ZSM-5/cordierite monolithic catalyst samples with different Si/Al ratios was carried out at 723 K and GHSV=10 000 h-1with NO ($ømega$ = 2 × 10-3) in He. The results indicated that a higher Si/Al ratio favors the conversion of NO. Little amount of NaO was found in the products when the reaction temperature was over 623 K. The turnover frequency (TOF) for NO decomposition on the Cu-ZSM-5/cordierite monolithic catalyst was higher than that on the pure Cu-ZSM-5 zeolite catalyst.

NK-101, a novel aluminophosphate with a thermostable microporous structure, has been successfully synthesized, using a template of p-dimethylamine pyridine in hydrothermal system. And the calcined sample was characterized by adsorption of n-hexane, XRD, SEM, IR,27Al and31P MAS-NMR. It has been proved that the novel zeolite has microporous property, with its pore size larger than 0.43nm. Its crystals are like rice corn. It is called NK-101 zeolite.