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Activity and selectivity of mono- and bimetallic catalysts containing nano-particles of gold stabilized by different supports are compared in dimethyldisulfide removal from air at 150–320 °C. TiO2-supported Au and Au–Pd samples demonstrate stable and efficient DMDS removal at temperature as low as 155 °C, with formation of the two products: SO2 and elemental S. On the contrary, no formation of elemental S is detected in the case of Au, Au–Rh, and Au–Pd catalysts supported on HZSM-5, H-beta, or MCM-41. The most active Au–Rh/HZSM-5 catalyst demonstrates an efficient DMDS removal at 290 °C, with quantitative DMDS-to-SO2 oxidation. Characterization of catalysts with TPR, XRD, and (XANES + EXAFS) confirms a high dispersion of the metallic phases in all catalysts under study. Specific interaction between nano-particles of gold and titanium dioxide surface could be responsible for the unusual catalytic behavior of Au/TiO2 samples, as distinct from Au/zeolitic systems. [ABSTRACT FROM AUTHOR]

In this study, novel SiO2- and Al2O3-supported Cu-Fe catalysts are developed for selective hydrogenation of 2-methyl-3-butyne-2-ol to 2-methyl-3-butene-2-ol under mild reaction conditions. TEM, XRD, and FTIR studies of adsorbed CO and TPR-H2 are performed to characterize the morphology, nanoparticle size, and particle distribution, as well as electronic state of deposited metals in the prepared catalysts. The deposition of Fe and Cu metal particles on the aluminum oxide carrier results in the formation of a mixed oxide phase with a strong interaction between the Fe and Cu precursors during the calcination. The highly dispersed nanoparticles of Fe2O3 and partially reduced CuOx, with an average size of 3.5 nm and with strong contact interactions between the metals in 5Cu-5Fe/Al2O3 catalysts, provide a high selectivity of 93% toward 2-methyl-3-butene-2-ol at complete conversion of the unsaturated alcohol. [ABSTRACT FROM AUTHOR]

Iron-modified platinum bimetallic system, 1% Pt–1% Fe/SiO 2 , provides selective liquid-phase hydrogenation of phenylacetylene into styrene at 70 °C and 5 atm. This effect is attributed to the electron enrichment of the Pt surface atoms due to a charge transfer from Fe to Pt or contact interactions between these two metals, as indicated by XPS and DRIFTS-CO. [ABSTRACT FROM AUTHOR]

A series of the Au–Cu/SiO 2 catalysts including low-loaded samples with an overall metal content less than 0.5 wt% was synthesized by a redox method. The catalysts were tested in the selective oxidation of ethanol to acetaldehyde. The highest catalytic activity was observed for the catalysts having the lowest metal content due to the presence of nanosized Au particles and the synergetic effect of Au–Cu 2+ interaction. Unusual reduction behavior was found for the catalysts with the 0.2 wt% content of Cu. XRD, TPR, EXAFS, and STEM techniques were applied for the catalysts characterization. [ABSTRACT FROM AUTHOR]