Interactions of nitrogen oxides (NO x ) with (n)MnO x −(1 − n)CeO2 binary oxides were studied to use them for sorptive NO x removal at low temperatures (≃150 °C). The formation of MnO x −CeO2 solid solutions with the fluorite-type structure at n ≃ 0.5 was found to be quite effective in accelerating NO x sorption from flowing mixtures of 0.08% NO, 2% O2, and He balance (W/F = 0.24 g·s/cm3). The cumulative NO x uptake was increased by decreasing the reaction temperature and/or by increasing O2 concentration, indicative of chemisorption via oxidation of NO/NO2. In situ FT-IR diffuse reflectance spectrometry demonstrated that adsorption of NO x as bidentate, monodentate, and ionic nitrates is responsible for the large uptake. These adsorbates are produced by oxidative adsorption, which is caused by NO oxidation to NO2 by lattice oxygens bound to Mn and subsequent coordination to Ce in adjacent surface sites. XPS and O2-TPD studies suggested that the active site for NO oxidation should be related to the redox of Mn and accompanying reversible sorption/desorption of lattice oxygens.

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