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ZnMeIIIFeO4 catalysts with different trivalent metal (MeIII = Fe, Al, Cr, Mn, and Co) were prepared by a co-precipitation method, and were applied to the oxidative dehydrogenation of n-butene to 1,3-butadiene. Successful formation of ZnMeIIIFeO4 catalysts was confirmed by XRD and ICP-AES analyses. Catalytic performance of ZnMeIIIFeO4 catalysts in the oxidative dehydrogenation of n-butene strongly depended on the identity of trivalent metal (MeIII). Acid properties of ZnMeIIIFeO4 catalysts were measured by NH3-TPD experiments, with an aim of correlating the catalytic performance with the surface acid property of the catalysts. It was revealed that yield for 1,3-butadiene increased with increasing surface weak-acid density of ZnMeIIIFeO4 catalyst. Among the catalysts tested, ZnFeFeO4 catalyst with the largest surface weak-acid density showed the best catalytic performance in the oxidative dehydrogenation of n-butene.

Palladium catalyst supported on SO3H-functionalized SBA-15 (denoted as Pd/SO3H-SBA-15) was applied to the direct synthesis of hydrogen peroxide from hydrogen and oxygen. For comparison, palladium catalyst supported on SBA-15 (denoted as Pd/SBA-15) was also employed for the direct synthesis of hydrogen peroxide. Selectivity for hydrogen peroxide, yield for hydrogen peroxide, and final concentration of hydrogen peroxide over Pd/SO3H-SBA-15 catalyst were much higher than those over Pd/SBA-15 catalyst. The high catalytic performance of Pd/SO3H-SBA-15 catalyst was attributed to the enhanced acid amount of SO3H-SBA-15 support, which served as an alternate acid source in the direct synthesis of hydrogen peroxide from hydrogen and oxygen.

An efficient method to enhance the catalytic properties of Zn-ferrite catalyst in the oxidative dehydrogenation of n-butene to 1,3-butadiene is proposed. The incorporation of phosphorous compound in Zn-ferrite is very effective to improve the catalytic activity as well as to maintain extremely long useful lives at high oxygen to n-butene ratio. It is found that the amount of phosphorous is critical and the presence of appropriate amount of phosphorous in catalyst may contribute the catalyst stabilization by which unfavorable reduction of Fe3+ sites to Fe2+ is effectively suppressed. This suggests that the oxygen mobility is maintained as high as the redox mechanism keeps constantly working. On the other hand, the effort to increase the population of mobile oxygen species by the introduction of external oxygen donor phase is found to be rather ineffective regardless of the external donor oxides used.

Two types of zinc ferrite catalysts have been prepared by physical mixing or coprecipitation and applied to the oxidative dehydrogenation of n-butene to 1,3-butadiene. It is observed that the catalytic activity is significantly dependent upon not only the crystallinity but also the composition of a ferrite catalyst. If crystallinity of a catalyst is too high, the oxygen spillover through the lattice is severely suppressed and results in low catalytic activity. On the other hand, the presence of α-Fe2O3 in ferrite structure may lead to decrease of the reaction performance. Coprecipitation with strong base such as NaOH is found to be one of the efficient methods to form a catalytically active ferrite structure in that it is advantageous to obtain pure ferrite composition with appropriate crystallinity. During catalyst preparation, complete removal of sodium is essential because the residual sodium in catalyst considerably reduces the reaction performance. Although the use of mild base such as NH4OH is advantageous to prevent the exhaustive washing, the formation of mixed phase both α-Fe2O3 and ZnFe2O4 may reduce n-butene conversion as well as 1,3-butadiene selectivity.

A series of metal ferrite (MeIIFe2O4) catalysts were prepared by a co-precipitation method with a variation of divalent metal component (MeII = Zn, Mg, Mn, Ni, Co, and Cu) for use in the oxidative dehydrogenation of n-butene to 1,3-butadiene. Successful formation of metal ferrite catalysts with a random spinel structure was confirmed by XRD, ICP-AES, and XPS analyses. The catalytic performance of metal ferrite catalysts in the oxidative dehydrogenation of n-butene strongly depended on the identity of divalent metal component. Acid properties of metal ferrite catalysts were measured by NH3-TPD experiments, with an aim of correlating the catalytic performance with the acid property of the catalysts. It was revealed that the yield for 1,3-butadiene increased with increasing surface acidity of the catalyst. Among the catalysts tested, ZnFe2O4 catalyst with the largest surface acidity showed the best catalytic performance in the oxidative dehydrogenation of n-butene.

Oxidative dehydrogenation of C4 raffinate-3 to 1,3-butadiene was carried out in a dual-bed reaction system comprising ZnFe2O4 and Co9Fe3Bi1Mo12O51 catalysts in order to investigate a synergistic effect of these two catalysts. Conversion of n-butene and yield for 1,3-butiadene obtained in a dual-bed reaction system comprising ZnFe2O4 (first-bed) and Co9Fe3Bi1Mo12O51 (second-bed) were higher than those obtained in a single-bed reaction system using either ZnFe2O4 or Co9Fe3Bi1Mo12O51. 1-Butene-TPD and 2-butene-TPD measurements revealed that ZnFe2O4 catalyst retained more selective oxygen species for the reaction with 2-butene than for the reaction with 1-butene, while Co9Fe3Bi1Mo12O51 catalyst retained more selective oxygen species for the reaction with 1-butene than for the reaction with 2-butene. The synergistic effect of ZnFe2O4 (first-bed) and Co9Fe3Bi1Mo12O51 (second-bed) catalysts in the oxidative dehydrogenation of C4 raffinate-3 was attributed to the combination of high catalytic activity of ZnFe2O4 for 2-butene and high catalytic activity of Co9Fe3Bi1Mo12O51 for 1-butene.

Titanium silicalite-1 (TS-1) catalyst was synthesized in the presence of polystyrene (PS) particles (denoted as TS-1_PS catalyst) for use in the epoxidation of propylene with hydrogen peroxide. For the purpose of comparison, TS-1 catalyst was also synthesized by a conventional method (in the absence of polystyrene particles). In the epoxidation of propylene, the TS-1_PS catalyst showed a higher conversion of hydrogen peroxide and a higher selectivity for propylene oxide (PO) than the TS-1 catalyst. Consequently, the TS-1_PS catalyst showed a higher yield for PO than the TS-1 catalyst. Characterization results showed that the high catalytic performance of TS-1_PS was attributed to the enhanced hydrophobic property of the catalyst and the suppressed formation of anatase TiO2 in the catalyst.

Zinc ferrite (ZnFe2O4) catalysts were prepared by a co-precipitation method using aqueous buffer solution with different pH (pH = 6−12), and applied to the oxidative dehydrogenation of n-butene to 1,3-butadiene. Conversion of n-butene and yield for 1,3-butadiene showed volcano-shaped curves with respect to pH value employed during the co-precipitation step. NH3-TPD experiments were conducted to correlate the acid property with the catalytic performance of zinc ferrite catalysts. It was revealed that the catalytic performance of zinc ferrite catalysts in the oxidative dehydrogenation of n-butene was closely related to the surface acidity of the catalysts. Conversion of n-butene and yield for 1,3-butadiene increased with increasing surface acidity of the catalysts. Among the catalysts tested, the zinc ferrite catalyst prepared at pH = 8 showed the best catalytic performance in the oxidative dehydrogenation of n-butene, which was attributed to its largest surface acidity.

Hydrogen was produced by methanol decomposition over cold-rolled foils of intermetallic compound Ni3Al which is known as an excellent high-temperature structural material. We found high catalytic activity and selectivity for methanol decomposition in flat cold-rolled Ni3Al foils. The catalytic activity was enhanced above 713 K by the spontaneous formation of fine Ni particles dispersed on carbon nanofibers during the reaction, resulting in high catalytic performance. The results demonstrate that the Ni3Al foils can be used both as catalyst precursors and as structural materials of microreactors for hydrogen production.