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Catalyst Deactivation Due to Glaze Formation from Oil-Derived Phosphorus and Zinc
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Abstract
The deactivation of automotive catalysts by engine oil-derived components of phosphorus and zinc can occur by the formation of an amorphous zinc pyrophosphate (Zn2P2O7) that is impervious to gas diffusion. The catalyst poison, derived from antiwear oil additive zinc dialkyl dithiophosphate (ZDP) in low-temperature exhaust environments, appears as glassy, amorphous deposits on catalysts as shown by scanning electron microscopy (SEM).
Laboratory studies were performed to understand the effects of exhaust stoichiometry, temperature, rate of oil burn, and chemical form of P and Zn compounds on glaze formation. The formation of the amorphous deposits using a laboratory pulsator apparatus showed that noncombusted ZDP causes the glaze formation. Electron microprobe studies indicated the association of P with Zn on precious metal films exposed to ZDP combustion products. Secondary ion mass spectrometry (SIMS) confirmed a similar P to Zn correspondence on the vehicle-aged catalysts. Once formed, the amorphous zinc pyrophosphate glaze could only be removed under high-temperature, reducing conditions which sintered the catalyst with no significant improvement in activity. Guidelines are presented for exhaust temperatures necessary for catalyst operation and prevention of catalyst deactivation by the formation of Zn pyrophosphate glaze.
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Williamson, W., Perry, J., Goss, R., Gandhi, H. et al., "Catalyst Deactivation Due to Glaze Formation from Oil-Derived Phosphorus and Zinc," SAE Technical Paper 841406, 1984, https://doi.org/10.4271/841406.Also In
References
- Gandhi H. S. Williamson W. B. Bomback J. L. “Deactivation of Three-way and Oxidation Catalyst Dual-Bed Emission Control Systems: Catalyst Post-Mortem Analyses from Methanol-Fueled Vehicles,” Appl. Catal. 1982 3 79
- Gandhi H. S. Piken A. G. Stepien H. K. Shelef M. DeLosh R. G. Heyde M. E. “Evaluation of Three-Way Catalysts, Part II,” SAE Paper 770196 1977
- Wotring W. T. Meguerian G. H. Gandhi H. S. McCuiston F. D. Piken A. G. “50,000 Mile Vehicle Road Test of Three-Way and NO X Reduction Catalyst Systems,” SAE Paper 780608 1978
- Spearot J. A. Caracciolo F. “Engine Oil Phosphorus Effects on Catalytic Converter Performance in Federal Durability and High-Speed Vehicle Tests,” SAE Paper 770637 1977
- Minamitani H. Ikuyama A. Machida C. Kawashima K. Matsudaira Y. Furui J. “Effects of Engine Oil Additives on the Activity of Exhaust Gas Oxidation Catalysts,” J. Japan Petrol. Inst. 1978 21 116
- Caracciolo F. Spearot J. A. “Engine Oil Additive Effects on the Deterioration of a Stoichiometric Emissions Control (C-4) System,” SAE Paper 790941 1979
- Monroe D. R. “Phosphorus and Lead Poisoning of Pelleted Three-Way Catalysts,” SAE Paper 800859 1980
- Williamson W. B. Perry J. Gandhi H. S. Bomback J. L. “Effects of Oil Phosphorus on Deactivation of Monolithic Three-Way Catalysts,”
- Acres G. J. K. Cooper B. J. Shutt E. Malerbi B. W. “Platinum Catalysts for Exhaust Emission Control: The Mechanism of Catalyst Poisoning by Lead and Phosphorus Compounds,” Adv. Chem. Series 1975 143 54
- Bomback J. L. Wheeler M. A. Tabock J. Janowski J. D. Environ. Sci. Technol. 1975 9 139
- Chou T. S. Hegedus L. L. “Transient Diffusivity Measurements in Catalyst Pellets with Two Zones of Differing Diffusivities,” AIChE J. 1978 24 225
- Hegedus L. L. McCabe R. W. “Catalyst Poisoning,” Catal, Rev.-Sci. Eng. 1981 23 441
- Angele B. Kirchner K. “The Poisoning of Noble Metal Catalysts by Phosphorus Compounds,” Chem. Eng. Sci. 1980 35 Schlosser E. G.
- Shelef M. Betta R. A. Dalla Larson J. A. Otto K. Yao H. C. “Poisoning of Monolithic Noble Metal Oxidation Catalysts in Automobile Exhaust Environment,” AIChE 74th National Meeting New Orleans 1973
- Toyo Kogyo Co., Ltd. “Exhaust Gas Purging Catalyst Without Phosphorus Poisoning,” Jpn. Kokai Tokkyo Koho 1980
- Toyo Kogyo Co., Ltd. “Prevention of Poisoning of Exhaust Gas Catalyst,” Jpn. Kokai Tokkyo Koho 1980
- Williamson W. B. Gandhi H. S. Weaver E. E. “Effects of Fuel Additive MMT on Contaminant Retention and Catalyst Performance,” SAE Transactions Paper 821193 1982 91 3694
- Spedding H. Watkins R. C. “The Antiwear Mechanism of ZDDP's, Part I” Tribology International 1982 15 9 Watkins R. C. 1982 15 13
- Otto K. Betta R. A. Dalla Yao H. C. “Laboratory Method for the Simulation of Automobile Exhaust and Studies of Catalyst Poisoning,” APCA J. 1974 24 596
- Gandhi H. S. Piken A. G. Shelef M. Delosh R. G. “Laboratory Evaluation of Three-Way Catalysts,” SAE Transactions 1976 85 2 901 SAE Paper 760201
- Gandhi H. S. Williamson W. B. Tabock J. Logothetis E. M.