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dispersion effect of cobalt spinel active phase spread over ceria for catalytic N2O decomposition: the role of the interface periphery, Applied Catalysis B, Environmental http://dx.doi.org/10. 1016/j.apcatb.2015.07.027 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. The catalytic tests in deN 2 O reaction revealed that the 10 wt.% of cobalt spinel in supported system is able to reproduce the activity of bare Co 3 O 4 catalyst. However, it was found that the catalyst with the lowest content of Co 3 O 4 equal to 1 wt.% exhibits the highest apparent reaction rate per mass of the spinel active phase. The observed activity was explained basing on the transmission electron microscopy analysis in terms of the dispersion of spinel phase over ceria support. A simple model that accounts for the observed strong dispersion effect is proposed. It consists in a two-step mechanism, where N 2 O is dissociated on the spinel nanograins and the resultant oxygen species are preferentially recombined at the Co 3 O 4 /CeO 2 interface periphery.

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The catalytic activity of a doubly promoted K/Zn−Co 3 O 4 spinel catalyst in the deN 2 O reaction was tested for 10 weeks in a nitric acid pilot plant. A charge of 15 kg of the catalyst was synthesized via precipitation method, dried, calcined, and formed into 5 × 5 mm tablets. The catalytic tests were carried out in the wide range of process parameters: 320 < T < 425 °C; 80 < V RG < 180 N m 3 •h −1 , 3 < p < 9.5 bar(a). During the operation the chemical composition of tail gases from ammonia oxidation reactor outlet varied within the following range: 300 < C N2O < 1500 ppm(v); 30 < C NOx < 3000 ppm(v); 10000 < C O2 < 50000 ppm(v); 1000 < C H2O < 18000 ppm(v); N 2 − rest. In these conditions, the N 2 O conversion was above 70% at 400 °C and was stable in time. Fresh and used catalysts were compared through detailed structural and morphological characterization (XRD, Raman, BET, SEM, XPS, H 2 -TPR), and their deN 2 O performance was verified in laboratory conditions. Long-term catalytic tests proved persistent stability of the catalyst with respect to its high activity, composition, structure, and morphology.

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