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Abstract Series of Fe-modified MnO 2 catalysts were prepared to improve low-temperature NO oxidation. Introduction of Fe3+ resulted in a phase transformation from α-MnO 2 to ε-MnO 2. Hexagonal Fe 0.32 MnO 2 exhibited the highest activity with the lowest T 50 of 156 °C and the maximum NO conversion of 80% at 250 °C. It also possessed the best reducibility and abundant readily available oxygen species, which facilitated the oxidation of NO. Major differences in the NO oxidation reaction route between α-MnO 2 and Fe 0.32 MnO 2 were the adsorption sites and the type of intermediates. The synergetic effect between Fe and Mn enhanced the activation of NO and O 2. Highlights • Hexagonal Fe 0.32 MnO 2 exhibited the highest NO oxidative activity with the T 50 of only 156 °C. • The introduction of Fe could greatly help to promote the reducibility and increase available oxygen species. • The introduction of Fe changed the type of intermediates during reactions. [ABSTRACT FROM AUTHOR]

Abstract: The catalytic performance of LaMeO3 (Me=Mn, Fe, Co) perovskite prepared by a sol–gel method was studied. These catalysts were characterized by X-ray diffraction (XRD), N2 adsorption (BET), H2 temperature programmed reduction (TPR), NO temperature programmed desorption (TPD) and CO–O2 pulse. LaCoO3 exhibited the best activity than that of LaFeO3 and LaMnO3 even after hydrothermal ageing. The activity sequence is in accordance with the reducibility of the samples. The activated oxygen species and adsorbed NO play key roles in the NO oxidation reaction. [Copyright &y& Elsevier]

Abstract: The simultaneous presence of sodium and copper on novel Na/Cu/CeO2 and Na/Cu/CeY catalysts resulted in a dramatic increase in the catalytic adsorption of NO. Copper catalyzes the oxidation of NO to NO2, which is further adsorbed by the sodium phase. The intimate contact of both phases favors the formation of nitrates on the surface. The cooperative effect between the copper and sodium phases increases the reduction temperature of copper. It was found that the addition of copper induced a stabilizing effect on the surface area of the catalysts. [Copyright &y& Elsevier]

Abstract: LaMn1− y Co y O3 (y =0–0.5) catalysts were synthesized by sol–gel methods and characterized by BET and XRD. The catalytic activities were non-linear enhanced by cobalt substitution, and achieved the highest level (76.5%) on LaMn0.9Co0.1O3. The reducibility was investigated by the oxygen storage capacity and H2-TPR measurements. The stability of Mn4+ and activated oxygen species may be the determined factors for NO oxidation reaction, which is attributed to the synergistic effect between cobalt and manganese. [Copyright &y& Elsevier]

Abstract: NO oxidation and NO x storage behavior of 1% Pt/10% BaO/Ce x Zr1− x O2 (x =0, 0.25, 0.5, 0.75, 1) catalysts prepared by the Pechini method were investigated via Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) spectroscopy. DRIFTS study revealed that in the presence of Pt/BaO/Ce0.5Zr0.5O2, NO is oxidized to NO2 in the absence of gas phase O2 at room temperature due to high oxygen mobility in the support material. [ABSTRACT FROM AUTHOR]

Abstract: A dramatic improvement of Cu/TiO2 as NO adsorbent was achieved by the addition of Na. It was observed that the improvement in NO adsorption was accompanied by the appearance of nitrate and nitrite species on the surface of the Na/Cu/TiO2 adsorbent. The presence of copper leads to an in situ oxidation of NO to NO2, which facilitates the formation and adsorption of nitrite and nitrates species. The presence of sodium results in less reducible copper species. [Copyright &y& Elsevier]