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Surface modification of SiO₂ supports was shown to significantly affect the properties of Pd/SiO₂ catalysts. The surface of SiO₂ can be modified by various pretreatment methods. In this study, the effect of different calcination temperatures on support surface was investigated. Pd supported on pretreated SiO₂ was characterized by H2 temperature-programmed reduction (TPR), XRD, CO chemisorption measurements, and field-emission transmission electron microscopy (FE-TEM). The silanol group (-OH), which is one of the functional groups of SiO₂, interferes with the reduction of palladium because it strongly bonds with palladium ions (-PdO) during the preparation of the catalyst. Due to the complete removal of silanol (Si-OH) groups following calcination at 700 °C, the metal reducibility was enhanced, and the catalyst pretreated at this calcination temperature exhibited the highest metal dispersion of 13.02%. Further, to confirm the catalytic activity of the prepared catalysts, hydrogenation of D-glucose was conducted. The HPLC results demonstrated that Pd/SiO₂_700 has the highest catalytic activity toward hydrogenation of D-glucose. Therefore, it was confirmed that the removal of silanol groups increase the metal dispersion and catalytic activity of Pd/SiO₂ catalyst.

Lead molybdate (PbMoO₄) materials were successfully synthesized using a facile surfactant-assisted microwave process and characterized by XRD, Raman, PL, BET and DRS. We also investigated the photocatalytic activity of these materials for the decomposition of Rhodamine B under UV-light irradiation. The XRD and Raman results revealed the successful synthesis of 42–69 nm, well-crystallized PbMoO₄ crystals with a facile surfactant-assisted microwave process. The PbMoO₄ catalysts prepared using microwave process enhanced the photocatalytic activity compared to PbMoO₄ catalyst prepared by hydrothermal method. The PbMoO₄ catalyst prepared at 100 °C showed the highest photocatalytic activity. The PL peak was appeared at about 540 nm for all catalysts and the excitonic PL signal was proportional to the photocatalytic activity for the decomposition of Rhodamine B.

The aim of this work is to be compared the effect of supports textural properties with pre-treatment method on dispersion of Pd particle. The CNTs were functionalized by different concentration of acid in order to obtain materials with different chemical and physical properties. The characteristics of functionalized CNTs were investigated by FT-IR and Rama spectropy. The Pd/CNTs catalysts prepared on support having the different surface properties were characterized by XRD, FE-TEM and CO-chemisorption. When pretreated 8M concentration, the CNTs has the highest amount of oxygen functional group and ID/IG ratio, in this study. Pd/CNT8M has high dispersion and small particle size. From these results, we confirmed that characteristics of Pd/CNTs catalyst such as particle size and dispersion of Pd are influenced by density of oxygen functional group and disorder of CNTs. And we have observed that acid treatment concentration of 8M is sufficient to functionalize the CNTs by introducing -COOH group of CNTs surfaces.

Pd/C catalysts were prepared by ion exchange in aqueous solution. Physical dispersion methods including sonication, high share mixer and stirrer were used for though high dispersion of carbon. The physical properties of the prepared Pd/C particles were investigated by BET, XRD, and FE-TEM. The dispersion of Pd nanoparticles on carbon was measured on the basis of CO adsorption capacity using a pulse technique. FE-TEM micrographs showed that Pd nano particles possessed a spherical morphology with a narrow size distribution, with particles sizes ranging from 2-25 nm. The Pd particles prepared using sonication and high share mixer are well dispersed compared to the stirrer method. In addition, metal dispersions as calculated by CO uptake were 11.3, 20.4, and 25.0% for the stirrer, sonication and high share mixer methods, respectively.

LaCoO3 perovskite type oxides were successfully prepared using microwave-assisted method, characterized by TG/DTA, XRD, XPS and H2-TPR and their catalytic activities for combustion of benzene were determined. Almost of catalyst showed perovskite crystalline phase and 13-84 nm particle size. LaCoO3 catalysts prepared by microwave-assisted method showed the highest activity and the conversion reached almost 100% at 360 degrees C. In the LaCoO3-type catalyst, the partial substitution of Sr into site A enhanced the catalytic activity on the combustion of benzene. The higher amount of the chemisorbed oxygen was, the better the performance of the combustion catalyst. The catalytic activity of perovskite-type oxides showed a good relationship with the results of H2-TPR and XPS measurement.

Cu-Zn-Al catalysts were prepared using microwave-assisted process and co-precipitation methods. The prepared catalysts were characterized by XRD, BET, XPS and TPD of ammonia and their catalytic activity for the hydrogenolysis of glycerol to propylene glycol was also examined. The XRD patterns of Cu/Zn/Al mixed catalysts show CuO and ZnO crystalline phase regardless of preparation method. The highest glycerol hydrogenolysis conversion is obtained with the catalyst having a Cu/Zn/Al ratio of 2:2:1. Hydrogen pre-reduction of catalysts significantly enhanced both glycerol conversions and selectivity to propylene glycol. The glycerol conversion increased with an increase of reaction temperature. However, the selectivity to propylene glycol increased with an increase of temperature, and then declined to 30.5% at 523 K.

Lead molybdate (PbMoO4) was successfully synthesized using a microwave-assisted method and characterized by XRD, Raman spectroscopy, SEM, PL and DRS. We also investigated the photocatalytic activity of these materials for the decomposition of Rhodamin B under UV-light irradiation. The XRD and Raman results revealed the successful synthesis of 42-52 nm, well-crystallized PbMoO4 crystals with the microwave-assisted hydrothermal method. The PbMoO4 catalysts prepared using the microwave-assisted process enhanced the photocatalytic activity compared to that prepared by hydrothermal method and the catalysts prepared at a solution pH = 11 and temperature of 105 degrees C showed the highest photocatalytic activity. The PL peaks appeared at about 540 nm for all catalysts and the excitonic PL signal was proportional to the photocatalytic activity for the decomposition of Rhodamin B.

In this study, LaMnO3 perovskite type oxides were successfully prepared using the malic acid method. The oxides were characterized by TG/DTA, XRD, XPS, TEM and H2-TPR and their catalytic activities for the combustion of benzene were determined. Almost all of the catalysts showed perovskite crystalline phase and had a particle size of 15-60 nm. The LaMnO3 catalysts prepared with more than 1.0 mol of malic acid showed the highest activity and the conversion reached almost 100% at 310 degrees C. The catalysts were modified to enhance the activity by substituting the metal at the A or B site of the perovskite oxides. In the LaMnO3-type catalyst, the partial substitution of Sr into site A enhanced the catalytic activity during benzene combustion. In addition, the partial substitution of Co into site B also increased the catalytic activity and the catalytic activity was in the following order: Co > Cu > Fe in the LaMn1_xBxO3(B = Co, Fe, Cu) type catalysts.

In this study, nanosized lead-substituted perovskite type oxides, La1_xPbxCoO3, were successfully synthesized using a microwave-assisted method and characterized by TG/DTA, XRD, XPS, TEM and DRS. We also investigated the photocatalytic activity of these oxides for the decomposition of methyl orange. From XRD results, metal replacement with the Pb ion in the crystal lattice does not change the high crystallinity of the perovskite structure. When Pb ions are substituted into site A, the particle size decreased when compared to lead-free LaCoO3 perovskite type oxide. In the of UV-Vis DRS analysis, all the catalysts displayed the similar absorption spectrum up to the visible region and the absorption band shifted to a higher wavelength on the lead-substituted LaCoO3 perovskite oxides when compared to the lead-free LaCoO3 oxide. From XPS results, chemisorbed oxygen was shown to play an important role in the photocatalytic decomposition of methyl orange and the higher chemisorbed oxygen content, the better the performance of the photocatalyst.

In this study, we have investigated the photocatalytic activity for the decomposition of methyl orange on the LaCoO3 perovskite-type oxides prepared using sol-gel method at different conditions. From the results of UV-Vis DRS, all the catalysts have the similar absorption spectrum up to visible region. The LaCoO3 catalyst prepared at 1.5 mol of malic acid and calcined at 350 degrees C shows the highest activity. The amount of photo absorption in the visible region is correlated with the photocatalytic activity. In addition, the chemisorbed oxygen plays an important role on the photocatalytic decomposition of methyl orange and the higher are the contents of chemisorbed oxygen, the better shows the performance of photocatalyst.

SBA-15 mesoporous materials were successfully prepared by the conventional hydrothermal method and TiO2 nanoparticles were supported on them using different loading methods. The synthesized materials were characterized and their activity as photocatalysts for the decomposition of methylene blue was evaluated. The loading of titanium dioxide on the framework of SBA-15 makes the pore diameter and pore volume decrease compared to that of SBA-15. The chelating method causes the support to have a much better dispersion capacity for TiO2 particles as compared to the other two methods. The TiO2 supported by chelating method showed the highest photocatalytic activity among the photocatalysts prepared by different method.

The catalytic combustion of benzene over copper oxide supported on SBA-15 was investigated. The catalysts were prepared by the using chelating method and characterized. It is clear that the loading of CuO on the silica matrix drastically decreases the surface area and pore volume of the catalysts, as would be expected for the incorporation of CuO. The catalytic activity increased with an increase of CuO loading ratio. When CuO loading reached 5.8 wt%, the total conversion temperature was lowered to 350 degrees C.