Atsushi Satsuma

The particle size effect of Pd nanoparticles supported on alumina with various crystalline phases on methane combustion was investigated. Pd/θ, α-Al₂ O₃ with weak metal-support interaction showed a volcano-shaped dependence of the catalytic activity on the size of Pd particles, and the catalytic activity of the strongly interacted Pd/γ-Al₂ O₃ increased with the particle size. Based on a structural analysis of Pd nanoparticles using CO adsorption IR spe

The effects of the Pd particle size and the Al2O3 crystalline phase of Pd/Al2O3 catalysts on the CH4 combustion in the presence of H2O were investigated. According to X-ray absorption fine structure (XAFS) measurements, it was revealed that, during the CH4 combustion, the Pd nanoparticles existed on the Al2O3 support as a PdO phase, while the crystallinity of PdO depended on the Pd particle size. On the basis of X-ray diffraction (XRD), amorphous PdO particles with a size of <7 nm exhibited low

Selective catalytic reduction of NO by hydrocarbons (HC-SCR) is one of the promising technologies for removal of NO in exhausts containing excess oxygen, such as diesel and lean burn gasoline engines. Supported Ag catalysts, especially Ag/Al2O3, are thought to be the promising candidates for use in diesel exhausts, as confirmed by several reports on engine bench tests. The HC-SCR performance of supported Ag catalysts is very sensitive to the reaction conditions, especially the type of hydrocarbo

The redox properties of supported Pd catalysts can directly affect their methane combustion activity. Here, the effect of the support on methane combustion was elucidated using Pd nanoparticles supported on various metal oxides (θ-Al2O3, γ-Al2O3, ZrO2, CeO2, MgO, La2O3, TiO2, SnO2, and Nb2O5). To eliminate the effect of Pd particle size and morphology, uniform Pd particles were synthesized in the liquid phase. Interestingly, the methane combustion activity formed a volcano plot when plotted agai

Design of solid acid catalysts is one of the key technologies to establish environmental friendly catalytic processes. Featuring cation-exchanged clay and metal salts of heteropolyacids as model solid acid catalysts, a strategy for design of active catalysts for green chemical and biomass conversion processes is discussed. The important role of solid Lewis acids was suggested in acetylation of alcohols with acetic anhydride by cation-exchanged clay, Friedel–Crafts acylation and alkylation of aro

The mechanistic cause of enhancement of C3H8-SCR activity by addition of H2 over Ag/Al2O3 was investigated with in-situ FT-IR spectroscopy. Under a flow of NO + C3H8 + O2, nitrates were mainly formed on Ag/Al2O3. An addition of H2 into a C3H8-SCR atmosphere increased the concentration of surface acetate significantly, but decreased the concentration of surface nitrates. Formation and consumption rates of acetate and nitrates were estimated with transient in-situ IR measurement. By the addition o

Supported Au nanoparticles showed efficient catalytic performance for the ring rearrangement of 5-hydroxymethylfurfural (HMF) to a cyclopentanone derivative, 3-hydroxymethylcyclopentanone (HCPN), by taking advantage of the selective hydrogenation on Au nanoparticles and the Lewis acid catalysis of metal oxide supports. Among various metal oxide supported Au catalysts, the highest yield of HCPN was obtained by using Au/Nb2O5 (86% yield).

Carbon supported Ru–Ir alloyed nanoparticle catalyst (Ru-Ir/C) was prepared. Ru-Ir/C improved hydrogen oxidation reaction activity under alkaline conditions in comparison with Ru/C, Ir/C, and Pt/C.

The size control of Ag into nanoclusters generates unique catalytic features of Ag on automotive emission control and environmentally friendly organic reactions. Hydrogen-assisted selective catalytic reduction of NO by hydrocarbons (H2–HC–SCR), which is one of the promising technologies for removal of NO in the diesel engine exhausts, results in the formation of Ag clusters on alumina or zeolites and enhancement of the conversion of NO into N2. A mechanistic study using in situUV-Vis, EXAFS, and

Acidic metal oxides, in particular Ta₂O₅, significantly enhanced the conversion of 5-hydroxymethylfurfural to a cyclopentanone derivative.