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The Role of Rhodium in Rh/Pt Catalysts for CO/HC/NOx and SO4 = Emission Control-The Influence of Oxygen on Catalyst Performance
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Abstract
THE USE OF Rh/Pt catalysts in automobile exhaust emission control is now well established. These catalysts are applicable in both the conventional CO/HC control system and the more novel TWC approach seeking to control CO, HC and NOx emissions simultaneously. During comparative investigations of Rh/Pt vs. Pt catalysts it has become apparent that Rh/Pt catalysts possess certain features which are absent in other noble metal combinations. Thus in general Rh/Pt catalysts show much greater ability to convert NOx under TWC conditions, and produce lower sulphate emissions under net oxidising conditions. On the other hand Rh/Pt can show lower HC conversion and durability than other noble metal combinations when operated under vast excess of oxygen.
Surface studies in this laboratory have revealed that these effects can be attributed in part to surface enrichment of the Rh/Pt system by the rhodium component. This is followed by oxidation to produce durable surface species which are inactive to sulphate formation, and reduce the activity of the catalyst to HC conversion. The role of such species in the conversion of NOx is discussed, and possible solutions to this problem outlined in terms of catalyst design criteria.
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Cooper, B., Harrison, B., Shutt, E., and Lichtenstein, I., "The Role of Rhodium in Rh/Pt Catalysts for CO/HC/NOx and SO4 = Emission Control-The Influence of Oxygen on Catalyst Performance," SAE Technical Paper 770367, 1977, https://doi.org/10.4271/770367.Also In
References
- Klimisch R.L. Taylor K.C. “Environmental Sci. Tech.” 7 127 1973
- Shelef M. Gandhi H.S. “Platinum Metals” 18 1 2 1974
- Gandhi H.S. Stepien H.K. Shelef M. SAE Paper 750177 “Automotive Engineering Congress” Detroit February 1975
- Acres G.J.K.
- Krause B. Bouffard R.A. Karmilovich T. Kayle E.L. SAE Paper 760091 “Automotive Engineering Congress” Detroit February 1976
- Hammerle R.H. Truex T.J. SAE Paper 760090 “Automotive Engineering Congress” Detroit February 1976
- Cooper B.J. Shutt E. Scullard M.J. SAE Paper 760035 “Automotive Engineering Congress” Detroit February 1976
- Taylor K.C. “The Catalytic Chemistry of Nitrogen Oxides” Klimisch R.L. Larson J.G. Plenum, N.Y. and London 1975
- Ohara T. “The Catalytic Chemistry of Nitrogen Oxides” Klimisch R.L. Larson J.G. Penum, N.Y. and London 1975
- Bond G.C. Sermon P. Knight S.J. Brunel University Uxbridge, U.K.
- Beltzer M. Campion R.J. Peterson W.L. SAE Paper 740286 “Automotive Engineering Congress” February 1974
- Exxon Research & Engineering May 30th 1974
- Philpott J.E. “Platinum Metal Rev.” 15 2 52 1971
- Busby J.A. London University 1976
- Sachtler W.M.H. Jongepier R. “J. Catalysis” 4 665 1965
- McKee D.W. Norton F.J. “J Phys. Chem.” 64 1952 1960
- Smithells C.J. Brandes E.A. “Metals Reference Book” 761 Butterworths London and Boston 1976
- Chaston J.C. “Platinum Metals Review” 9 2 51 1965
- Darling A.S. “International Metallurgical Reviews” 175 1973
- Gandhi H.S. Piken A.G. Shelef M. DeLosh R.G. SAE Paper 760201 “Automotive Engineering Congress” Detroit February 1975
- Acres G.J.K. Cooper B.J. Shutt E. Malerbi B.W. “Catalysts for the Control of Automotive Pollutants” Advances in Chemistry 143 American Chemical Society Washington, D.C. 1975 54 71