A Miura of the Painlevé I Equation and Its Discrete Analogs

We present Miura transformations for the continuous and several discrete Painlev\'e I equations. In the case of the continuous P_I, we use the Hamiltonian formulation of the Painlev\'e equations and show that there exists a Miura transformation between P_I and the binomial, second degree, equation of Cosgrove SD_V. In the case of the discrete P_I's we obtain two different kinds of Miuras. One kind relates a d-P_I to some other d-P_I while the other leads to discrete four-point equations which are the discrete analogs of the derivative of Cosgrove's equation SD_V.     

Oxidant‐Free Dehydrogenation of Alcohols Heterogeneously Catalyzed by Cooperation of Silver Clusters and Acid–Base Sites on Alumina

Trifunctional green catalysis : In‐depth characterization shows that oxidant‐free selective oxidation of alcohols by silver nanoparticles on γ‐Al₂O₃, as a new heterogeneous catalyst, proceeds through cooperation of silver, acid, and base sites (see figure).

     

Number of surface redox sites of V-Sb-O catalysts

The NARP technique was applied for the measurement of surface redox sites of V-Sb-oxide catalysts. The profile of produced nitrogen in the NARP measurement was composed of two parts; the initial sharp peak and the tailing part, those represented the contribution of surface redox sites and regeneration step of the redox sites with lattice oxygen, respectively. The surface concentration of redox sites determined from the initial sharp peak was almost equivalent to the surface concentration of vanadium ions above surface Sb/V ratio of 1.0. The role of V-O-Sb sites on VSbO₄ surface as redox sites was suggested. The tailing part was broader than that of V₂O₅ at the same temperature range because of the faster regeneration step relative to that in V₂O₅. The surface concentration and the regeneration of redox sites strongly depend on the preparation method.     

Determination of surface V=O species of V2O5 catalysts during reaction condition by using in-situ Narp technique

NARP (Nitric oxide-Ammonia Rectangular Pulse) technique was applied for the in-situ measurement of the number of surface V=O species of V₂O₅ catalysts. When V₂O₅ catalyst was exposed to flowing benzene/O₂/N₂ mixture gas at 573–673 K, the surface concentration of V=O species decreased and finally reached a steady state which was dependent on the [O₂]/[Benzene] ratio in the feed gas. It was confirmed by XPS spectra that the decrease in the surface V=O species is attributed to the reduction of the V₂O₅ surface. Although calcination of V₂O₅ at above 873 K reduced the surface concentration of V=O species, it recovered after a cyclic reduction-oxidation treatment at 673 K, which modifies the near-surface layer of V₂O₅. The dependence of the surface V=O species on calcination temperature was correlated with the flatness of the surface and the diffusion of lattice oxygen in near-surface layer.     

The Toda molecule equation and the -algorithm

One of the well-known convergence acceleration methods, the -algorithm is investigated from the viewpoint of the Toda molecule equation. It is shown that the error caused by the algorithm is evaluated by means of solutions for the equation. The acceleration algorithm based on the discrete Toda molecule equation is also presented.

     

Selective oxidation of n-butane over Fe-promoted vanadyl pyrophosphate prepared from modification of nano-sized interlayer of lamellar vanadyl benzylphosphate

A novel approach for the preparation of promoted vanadyl pyrophosphate in well-defined structure was examined. Lamellar vanadyl benzylphosphate (LVBP) was used as a host material and iron acetylacetonate as a guest. It was found that iron acetylacetonate was successfully inserted into the interlayer of LVBP by heating of LVBP and iron acetylacetonate in toluene solution. Calcination of this in tercalated material resulted in a well-crystallized vanadyl pyrophosphate phase with uniform dispersion of Fe in bulk and surface. The obtained Fe-promoted vanadyl pyrophosphate showed an enhancement in the activity for selective oxidation of n-butane, especially at high temperature and long contact time.     

Surface oxygen-assisted Pd nanoparticle catalysis for selective oxidation of silanes to silanols

Just add O(2): Based on the fact that an oxygen-adsorbed Pd metal surface shows higher reactivity for water dissociation than a clean Pd surface, carbon-supported Pd nanoparticles (NPs) with surface oxygen atoms were developed as a highly effective and reusable heterogeneous catalyst for selective oxidation of silanes to silanols with water as a green oxidant (see figure).     

Metal Oxide Catalysts for Selective Reduction of NOx by Hydrocarbons: Toward Molecular Basis for Catalyst Design

Metal oxides are stable and highly durable catalysts for the selective catalytic reduction (SCR) of NO by hydrocarbons and potential candidates for practical use. This review focuses on the development as well as the fundamental understanding of metal oxide based catalysts for selective reduction of NO by hydrocarbons. Our studies on the SCR-deNOx properties of Ga₂O₃/Al₂O₃, Cu-Al₂O₃, and Ag-Al₂O₃ catalysts are presented and it is attempted to demonstrate the advantages of this type of catalysts. On the basis of several spectroscopic characterizations, the effect of important factors, such as dispersion, coordination, and the electronic states of the metal cation, on the intrinsic catalytic activity are quite well clarified. From the in situ FTIR results, the reaction mechanism is understood in terms of formation and reaction of surface molecules. The structural and kinetic information obtained at the molecular level provides a useful strategy for designing better deNOx catalysts using metal oxides.