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Direct Catalyst Monitoring by Electrical Means: An Overview on Promising Novel Principles


By measuring the electrical properties of the catalyst coating itself, one can observe directly and in situ the state of TWC, LNT, and SCR catalysts. Two principles are possible: a contact method, for which the coating is applied to planar electrodes and the electrical impedance is measured, and a non-contact method, in which the coating material is penetrated by radio frequency waves. In either case, the catalyst state is directly correlated with the measured transmission or reflection characteristics of the electrical sensors.

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The authors are indebted to Umicore (Dr. J. Gieshoff, Dr. U. Göbel, Dr. M. Rösch, Dr. M. Votsmeier) for providing catalyst samples.

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Correspondence to Ralf Moos.

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Moos, R., Wedemann, M., Spörl, M. et al. Direct Catalyst Monitoring by Electrical Means: An Overview on Promising Novel Principles. Top Catal 52, 2035–2040 (2009).

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  • Catalyst status detection
  • On-Board Diagnosis (OBD)
  • Exhaust gas sensor
  • TWC
  • LNT