Contact dynamics for a solid–solid reaction mediated by gas-phase oxygen Study on the soot oxidation over ceria-based catalysts.pdfVIP

Applied Catalysis B: Environmental 199 (2016) 96–107 Contents lists available at ScienceDirect Applied Catalysis B: Environmental journal homepage: /locate/apcatb Contact dynamics for a solid–solid reaction mediated by gas-phase oxygen: Study on the soot oxidation over ceria-based catalysts Marco Piumetti a, Bart van der Linden b, Michiel Makkee b, Paolo Miceli a, Debora Fino a, Nunzio Russo a, Samir Bensaid a,? a Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy b Catalysis Engineering, Department of Chemical Engineering, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands article info Article history: Received 4 April 2016 Received in revised form 27 May 2016 Accepted 2 June 2016 Available online 4 June 2016 Keywords: Ceria Soot-catalyst contact points Accessible surface area Soot oxidation Nanostructured ceria Nanocatalysts abstract Ceria-based catalysts with different topological and textural properties have been prepared to study the role of the soot-catalyst contact on the soot oxidation reaction. The physico-chemical features of the catalysts have been investigated by means of complementary techniques, such as powder XRD, N2 physisorption at ?196 ?C, optical microscopy at variable temperature, FESEM, TEM, and thermogravimetric analysis. As a whole, the best catalytic activity has been obtained with the CeO2-nanocubes (denoted to as “CeNC”) because of their higher intrinsic reactivity. On the other hand, high-surface area materials prepared by the cerium nitrate decomposition (denoted to as “Ce-ND”) or hydrothermal route (CeO2-stars, referred to as “Ce-SAS”) resulted less effective toward the soot combustion, con?rming the surface-sensitivity for this reaction. Moreover, it has been proven a higher dependence of the oxidation activity on the catalyst-to-soot ratio (wt./wt.) for the nanostructured catalyst (Ce-NC) exhibiting the lowest BET