NOx storage-reduction catalysts: Similarities and differences between Ba and K

Charles  Peden, Pacific Northwest National Laboratory

NOx storage-reduction (NSR) catalysts are one of the potential options for removing NOx from diesel engine exhaust. In the NSR technology, alkali or alkaline earth elements (K or Ba) take up NOx under lean operation and store them as nitrates, which are subsequently reduced during rich operation. In this presentation, we compare the characteristics of Ba and K storage elements during NOx adsorption and desorption processes using multiple techniques, including TR-XRD, FTIR and NO2 TPD. We find that, although both elements store NOx as nitrates, there are significant differences between the morphology changes of the Ba and K nitrates.

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