Yukiyoshi Ono

Catalytic combustion of odors in domestic spaces on ion-exchanged zeolites

Abstract Performance of ZSM-5 zeolites, ion-exchanged with different kinds of metals (Me/H-ZSM-5; Me=Cu, Zn, Mn, Fe, Co, and Ni) and H-ZSM-5 itself, was investigated for the catalytic combustion of trimethylamine (TMA), which is one of the typical odors in domestic spaces. The highest activity was achieved on both Cu/H-ZSM-5 and Fe/H-ZSM-5. The activity of Cu/H-ZSM-5 for the combustion increased with an increase in the amount of ion-exchanged Cu. TPD and FT–IR for the catalysts were measured to investigate the role of ion-exchanged metals in the catalytic combustion of TMA, and it was found that the metals weakened the strong acid sites of H-ZSM-5, and strongly interacted with TMA adsorbed.

Non-linear change in oxidation state of Cu during Co oxidation on supported copper catalysts measured by the forced-oscillating reaction method

Abstract In order to investigate the redox processes of the catalyst during the reaction, CO oxidation test on Cu-containing zeolite A (Cu-A), Cu ion-exchanged zeolite A (Cu/A), and Cu supported on silica gel (Cu/SiO 2 ) was carried out by using the forced-oscillating reaction method (FORM). The test was conducted under four different conditions, reductive reaction condition with large excess of CO, stoichiometry reaction condition with slight excess of CO, stoichiometry reaction condition with slight excess of O 2 , and oxidative reaction condition with large excess of O 2 . The order of activity for the CO oxidation was Cu-A>Cu/A, Cu/SiO 2 . The highest activity of Cu-A was ascribed to the more stable and lower oxidation state of Cu than that in Cu/A and Cu/SiO 2 . It was confirmed that the FORM was useful to investigate the changes of oxidation state and the property of catalyst in the CO oxidation.

Relationship between oxidation states of copper supported on alumina and activities for catalytic combustion of NH3

The relationship between the oxidation state of Cu supported on an alumina catalyst (Cu/Al2O3) and the activity for combustion of NH3 was investigated. Combustion of NH3 on the catalyst treated in hydrogen at 800°C occurred at lower temperature than on the catalyst treated in air. It was also much better than Pt and Rh catalysts for the conversion of NH3 to N2. Characteristics of the catalyst were investigated by XRD, XPS, and the N2O pulse injection method to understand the reason of its high catalytic activity. The reason of the high activity of the catalyst treated in hydrogen at the high temperature was attributed to the lower oxidation state of Cu in the catalyst.