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Volume 20, Issue 2
  • ISSN: 0032-1400


The installation of platinum group metal catalysts on 1975 model year U.S. automobiles for control of CO/HC emissions has led to concern over the tendency of such catalysts to oxidise SO to sulphuric acid aerosol. Examination of sulphate emissions from Johnson Matthey and Volkswagen test vehicles suggests that although there is some tendency to form sulphate, especially under highly oxidising conditions, the levels of sulphate are in general low. Comparison of measured sulphate conversion with thermodynamic equilibrium values shows that only a small fraction of the available exhaust SO is converted to sulphate, and that the catalyst’s ability to convert is shortlived. Future moves toward a three-way catalyst capable of simultaneously converting CO/HC and NO pollutants should eradicate any tendency towards sulphuric acid formation in automobile exhaust.


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  1. Bodenstein M., and Fink C. G. Z. Phys. Chem. (Leipzig), 1907, 60, (1), 46 [Google Scholar]
  2. Beltzer M., Campion R. J., Harlan J., and Hochhauser A. M. “The Conversion of SO2 over Automotive Oxidation Catalysts”, SAE paper 750095, February 24–28, 1975, Detroit, Michigan [Google Scholar]
  3. Hunter J. E. “Studies of Catalyst Degradation in Automotive Emission Control Systems”, SAE paper 720122, January 1972, Detroit, Michigan [Google Scholar]
  4. Hammerle R. H., and Mikkor M. “Some Phenomena which Control Sulphuric Acid Emission from Automotive Catalysts”, SAE paper 750097, February 24–28, 1975, Detroit, Michigan [Google Scholar]
  5. Vyehara O. A., and Watson K. M. Ind. Eng. Chem., 1943, 35, 541 [Google Scholar]

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  • Article Type: Research Article
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