New Oxygen Storage Components for Oxidation and Reduction in Automotive Catalysts – CORAL
Diesel Oxidation Catalysts (DOC) was developed to oxidize CO and hydrocarbons. NO oxidation is also expected reach the NO2/NOx ratios suitable for the downstream system of Selective Catalytic Reduction (SCR) of NOx by ammonia or urea.
The CORAL consortium will contribute to finely tune the composition, structure, texture, oxygen mobility and storage of Ce/Pr/Zr based oxides (REO) to design more effective and robust DOC and SCR catalysts compared with state-of-art ones. Based on the good knowledge of the consortium on the CeO2-ZrO2-PrOx phase diagram, two main families corresponding to (Ce,Pr)-rich phases with a rather high rate of Pr4+ suitable for the DOC application and Zr-rich domain with a large content of Pr3+ appropriate for SCR technology, will be considered.
The first objective of the CORAL project is to optimize the Pr content by exploring in more details the CeO2-ZrO2-PrOx phase diagram. The second objective is to directly incorporate PGM (Platinum Group Metal) during the synthesis of complex mixed oxides to control its rate and nature for the DOC function by hydrothermal reactions. A third objective is to stabilize a low concentration of Fe3+/Fe2+ as Lewis acids in the vicinity of Rare Earth Oxide (REO) to improve the SCR efficiency. To limit the risks, optimize the surface areas, phase purity and thermal stability, hydrothermal routes will be suitable to incorporate Transition Metals (TM) into the REO. Other TM such as Nb5+ (a Lewis acid) will be also tested.
The catalytic activity of PGM/REO systems for hydrocarbons combustion is strongly related to the oxygen mobility of REOs supports. Then in a fourth objective, the oxygen mobility under real conditions will be evaluated by several complementary methods both on dense materials and powders with high surface areas. In a fifth objective dedicated to PGM/(Ce,Pr)rich mixed oxides, three oxidation reactions to evaluate DOC performances will be followed: CO, C3H8 and NO oxidation, whereas for Zr-rich phases, the Urea-SCR performances in “real” condition will be measured at the laboratory scale. Finally, in the last objectives, these innovative catalytic materials will be characterized using valuable techniques such as E-TEM (Environmental Transmission Electron Microscopy) to observe and understand PGM/REO interactions at the nanoscale, and Infrared/Raman spectroscopies carried out under operando conditions to test the properties of the new materials for DOC and SCR applications, under realistic conditions.
Four inter-dependent work packages are proposed involving four academic partners (ICMCBordeaux, IC2MPoitiers, IRCELYON, LCS-ENSICaen).
The CORAL project is inserted in the “Défi#3” related to ‘Stimuler le renouveau industriel’ with the development of new heterogeneous catalysts for the environment protection. Moreover, this project ideally fits with the objectives of the orientation#14 : ‘Conception de nouveaux matériaux’.
The PSA group as car manufacturer has a strong interest in fundamental research in this domain and especially the targeted technological breakthroughs. In case of success, PSA is committed to valorize the results of the CORAL consortium and to evaluate the most effective CORAL innovative catalysts in real operating conditions.
Monsieur Alain Demourgues (ICMCB)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
IRCELYON CNRS Institut de Recherches sur la Catalyse et l'Environnement de Lyon
IC2MP Institut de Chimie des Milieux et Matériaux de Poitiers
LCS Laboratoire Catalyse et Spectrochimie
Help of the ANR 470,417 euros
Beginning and duration of the scientific project: - 48 Months