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Abstract: A methodology for the evaluation of diesel soot oxidation catalysts by high-throughput (HT) screening was developed. The optimal experimental conditions (soot amount, catalyst/soot ratio, type of contact, composition and flow rate of gas reactants) ensuring a reliable and reproducible detection of light-off temperatures in a 16 parallel channels reactor were set up. The temperature profile measured in the catalyst/soot bed under TPO conditions when the exothermic combustion of soot takes place was shown to provide an accurate measurement of the ignition. Its reproducibility and relevance were checked. The results obtained with a reference noble metal free catalyst (La0.8Cr0.8Li0.2O3 perovskite) agree very well with literature data. Qualitative mechanistic features could be derived from these experiments, stressing the likely limiting step of oxygen transfer from catalyst surface to soot particulates to ignite the soot combustion. Ceria material was shown to be more appropriate than perovskite one. From an HT screening of a large diverse library (over 100 mixed oxides catalysts) under optimized conditions, about 10 new formulations were found to perform better than selected noble metal free reference materials. [Copyright &y& Elsevier]

An accelerated investigation of various ceria-supported platinum catalysts by means of parallel synthesis and testing reactors is reported. The aim is to discover new catalysts for purifying hydrogen for fuel cells and other applications by studying three reactions: selective CO oxidation in the absence and in the presence of hydrogen (SelOx), water–gas shift (WGS), and reverse water–gas shift (RWGS). A set of catalysts is prepared by impregnating platinum on various doped ceria supports. These catalysts display, despite their nearly identical X-ray crystal structures, diverse redox/acidic/basic properties and different selectivities in the three test reactions. The best SelOx catalysts are also the most active for WGS/RWGS equilibration. In contrast to the conventional two-stage approach of discovery screening followed by lead optimization, we demonstrate that it is possible to extract valuable mechanistic information directly from the discovery stage. Specifically, we elucidate the elementary steps coupling the SelOx and WGS processes and gain insight as to the combined effects of hydrogen presence and cation doping on the CO oxidation reaction. [Copyright &y& Elsevier]