TiO₂ (P25)-supported Au-Pd bimetal nanoparticles displayed excellent performance in the solvent-free benzyl alcohol catalytic oxidation. However, little research attention has been paid to investigate the effects of TiO₂ form on the catalytic activity of Au-Pd/TiO₂. In the present research, rutile, brookite, and anatase TiO₂ were successfully synthesized and subsequently applied as the carrier to load Au-Pd nanoparticles by the deposition-precipitation method. The experimental results indicated that the benzyl alcohol conversion employing the rutile TiO₂-supported Au-Pd catalyst is higher than the conversion of anatase and brookite TiO₂-loaded Au-Pd catalysts. However, the Au-Pd/TiO₂-rutile displayed the lowest and highest selectivity toward benzaldehyde and toluene, respectively. ICP-AES, XRD, XPS, and TEM were conducted to characterize these catalysts. The corresponding experimental results revealed that the excellent performance of Au-Pd/TiO₂-rutile catalyst was attributed to both the smaller Au-Pd nanoparticle size distribution and the higher concentrations of O_α and Pd²⁺ species on the catalyst surface. In the recycle experiments, the Au-Pd/TiO₂-rutile catalyst displayed lower reaction stability compared with the Au-Pd/TiO₂-anatase and Au-Pd/TiO₂-brookite, which might be due to the coverage of larger amount of aldehyde products on the surface.

A series of MoO3 doped Fe2O3 catalysts prepared by the co-precipitation method were investigated in the selective catalytic reduction of NO by NH3 (NH3-SCR). The catalysts displayed excellent...

A series of Cu-SSZ-13@CeO₂ catalysts with surface modification with CeO₂ was prepared by the modified self-resemble method based on the one-pot synthesized Cu-SSZ-13 catalyst and applied for the selective catalytic reduction of NO by NH₃. The low-temperature catalytic activity and the tolerance to SO₂ + H₂O of Cu-SSZ-13@CeO₂ were found to enhance markedly compared with Cu-SSZ-13. In parallel, the XRD, N₂-BET, H₂-TPR, SEM, XPS, and in situ DRIFTS were performed to characterize the catalysts. XRD and SEM results proved that the surface of Cu-SSZ-13 was covered by nanoparticles of CeO₂. XPS results further confirmed that Ce species were in the outer of the catalysts. N₂-BET indicated that the physical structure parameters of the Cu-SSZ-13@CeO₂ were changed obviously due to the coverage of CeO₂. H₂-TPR suggested that the redox properties of the Cu-SSZ-13@CeO₂ catalysts were improved compared to the unmodified Cu-SSZ-13. In situ DRIFTS results demonstrated that the intensities of the bands attributed to NH₃ and NO_x species on the surface of Cu-SSZ-13@CeO₂-2 enhanced due to the CeO₂ modification, which played an important role for the NH₃-SCR performance.

A series of Pd/g-C₃N₄ catalysts were synthesized using different graphitic carbon nitride precursors, and were found to exhibit significant variations in catalytic performance for solvent-free selective catalytic oxidation of benzyl alcohol. Through comprehensive characterization (XRD, N₂-BET, ICP-AES, TEM, and XPS), the experimental results found that the nitrogen chemical configuration and surface Pd²⁺concentration critically determined the catalytic efficiency. Among the various nitrogen species, N-(C)₃-type nitrogen demonstrated the strongest influence on catalytic activity, which was positively correlated with its abundance in g-C₃N₄ matrices. In particular, g-C₃N₄ derived from dicyandiamide contained the highest N-(C)₃ type nitrogen content. When serving as Pd nanoparticle support, this material simultaneously achieved the best Pd²⁺ surface concentration and catalytic performance compared to the other g-C₃N₄-supported catalysts.

A series of Cu-SSZ-13 catalysts with different Si/Al molar ratio (10.6, 13.0, and 16.0) were prepared via one-pot method and investigated for the selective catalytic reduction by NH₃. It was found that Cu-SSZ-13 with Si/Al ratio of 13.0 exhibited the best NH₃-SCR performance with more than 94% NO conversion from 200 to 550°C. The influence of Si/Al molar ratio on the physical structure, redox behavior, surface acidity and Cu species distribution on the Cu-SSZ-13, together with the NH₃ and nitrate adsorption species on the surface of Cu-SSZ-13 were characterized by N₂-BET, XRD, NH₃-TPD, H₂-TPR, XPS, and in-situ DRIFTS, respectively. The characterization results indicated that the BET surface area, zeolite structure, surface acidity, redox properities, Cu²⁺ concentration, NH₃ and nitrate adsorption species on the catalyst surface were closely related to the Si/Al ratio, all of these factors played important roles in the NH₃-SCR performance for the Cu-SSZ-13.