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Received January 22, 2026
Revised May 8, 2026
Accepted May 8, 2026
Available online June 1, 2026
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귀금속 및 세륨 함량 변화에 따른 모놀리스 삼원촉매의 성능
Performance of Monolithic Three-Way Catalysts with Various Precious Metal and Cerium Loading
Rowan University
bae@rowan.edu
Korean Chemical Engineering Research, August 2026, 64(3), 105167
https://doi.org/10.9713/kcer.2026.64.3.105167
https://doi.org/10.9713/kcer.2026.64.3.105167
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Abstract
본 연구에서는 삼원촉매인 Pd-Rh-CeO2 기반 모노리스 촉매의 귀금속과 CeO2 함량이 삼원촉매 가동 공연비에 끼치는 영향에 대해 조사했다. 또한, 각 삼원촉매의 노화가 끼치는 영향을 탐색하기 위해서 1050 °C 조건에서 30시간동안 수열노화처리를 진행했다. 삼원촉매를 자동차 모의 배기가스 반응실험을 통해 100–500 °C의 활성을 시험한 결과, 양론 조건 (λ = 1.00)에서는 CeO2의 함량 증가가 촉매의 NO 환원과 C3H8 산화를 촉진하는 것으로 나타났다. 그와 대조적으로 과농과 희박 조건(λ = 0.99와 1.01)에서는 삼원촉매 활성이 CeO2보다 귀금속 함량에 영향을 받는 것으로 나타났지만, CeO2의 함량 변화가 과농 조건에서는 귀금속 함량이 높은 촉매군에서, 희박 조건에서는 과량의 O2에 의해 CeO2의 산소 결함 및 H2O 활용 효과가 제한되는 조건에서 C3H8 산화를 저하시키는 것으로 확인됐다. 이때, NO 환원 중에 생성될 수 있는 N2O는 CeO2 함량이 낮을수록 높은 생성량을 보였으나, 이와 대조적으로 NH3는 CeO2 함량이 높을수록 높은 생성량을 보였다. 결과적으로 CeO2 함량은 실제 구동 조건에 포함되는 과농 및 희박 조건에서 C3H8 산화 활성에 기여하며, N2O와 NH3의 생성량을 조절하는데 효과적으로 작용할 수 있다. 마지막으로 수열노화처리 이후 삼원촉매의 성능은 CeO2 함량이 높을수록 성능 저하가 다소 높게 나타났으며, CeO2 함량과는 관계없이 비슷한 성능으로 나타났다.
We investigated effects of the precious metal and CeO2 loading on the performance of Pd-Rh-CeO2 based monolithic three-way catalysts. To explore the impact of aging, hydrothermal aging was also conducted at 1050 °C for 30 h. Under stoichiometric condition (λ = 1.00), the performance with simulated automotive exhaust at 100–500 °C revealed that increase in CeO2 loading enhanced the NO and C₃H₈ removal. In contrast, under rich and lean conditions (λ = 0.99 and 1.01, respectively), the overall performance was more strongly governed by precious metal loading than by CeO2 loading. In particular, excessive CeO2 loading tended to suppress C3H8 oxidation under conditions where NO2 formation or steam reforming was not favored, although the effect depended on PGM loading and A/F ratio. Simultaneously, N2O was more formed under NO reduction with lower CeO2 loading, but NH3 was more formed at higher CeO2 loading. Finally, after hydrothermal aging treatment, the deactivation of catalysts significantly occurred with increasing CeO2 loading, and the aging performance appeared similar regardless of the CeO2 content.
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3. Haneda, M., Shinoda, K., Nagane, A., Houshito, O., Takagi, H., Nakahara, Y., Hiroe, K., Fujitani, T. and Hamada, H., “Catalytic Performance of Rhodium Supported on Ceria–zirconia Mixed Oxides for Reduction of NO by Propene,” J. Catal., 259, 223(2008).
4. Ho, P. H., Shao, J., Yao, D., Ilmasani, R. F., Salam, M. A., Creaser,
D. and Olsson, L., “The Effect of Pt/Pd Ratio on the Oxidation Activity and Resistance to Sulfur Poisoning for Pt-Pd/BEA Die- sel Oxidation Catalysts with High Siliceous Content,” J. Envi- ron. Chem. Eng., 10(4), 108217(2022).
5. Wang, J., Chen, H., Hu, Z., Yao, M. and Li, Y., “A Review on the Pd-based Three-way Catalyst,” Catal. Rev., 57, 79(2014).
6. Shelef, M. and Graham, G. W., “Why Rhodium in Automotive Three-way Catalysts?,” Catal. Rev., 36, 433(1994).
7. Jang, B. H., Kim, C. H., Oh, Y. S., Kim, S. D., and Lee, J. E.: “Effect of Alkaline Earth/Rare Earth Addition on the Heat Resis- tance of Pt: Rh Three Way Catalysts,” KCER, 39(2), 131(2001).
8. Matsouka, V., Konsolakis, M., Yentekakis, I. V., Papavasiliou, A., Tsetsekou, A. and Boukos, N., “Thermal Aging Behavior of Pt-only TWC Converters Under Simulated Exhaust Conditions: Effect of Rare Earths (CeO2, La2O3) and Alkali (Na) Modifi- ers,” Top. Catal., 54(16), 1124(2011).
9. Vasile, E., Ciocanea, A., Ionescu, V., Lepadatu, I., Diac, C. and Stamatin, S. N., “Making Precious Metals Cheap: A Sonoelec- trochemical–Hydrodynamic Cavitation Method to Recycle Plat- inum Group Metals From Spent Automotive Catalysts,” Ultrason. Sonochem., 72, 105404(2021).
10. Cooper, J. and Beecham, J., “A Study of Platinum Group Metals in Three-way Autocatalysts,” Plat. Met. Rev., 57, 281(2013).
11. Jeong, J., Choi, B., Jung, M. and Son, G., “Effects of the Precious Metal Composition in the Double Layer Wash-coat Tri-metal TWC for Low Emission Vehicles,” SAE Technical Paper, 2003-01- 1873(2003).
12. Pothen, F. and Fink, K., “A Political Economy of China's Export Restrictions on Rare Earth Elements,” ZEW Discussion Papers, No. 15-025(2015).
13. Rahimi Mashkaleh, M., Zamani, Y., Baniyaghoob, S. and Ganji Babakhani, E. “Synergistic Effects of Cerium and Strontium Pro- moters on Copper‐Modified Iron‐Based Fischer–Tropsch Synthe- sis Catalysts,” Appl. Organomet. Chem., 39(2), e7844(2025).
14. Baik, J. H., Yim, S. D., Nam, I. S., Mok, Y. S., Lee, J. H., Cho,
B. K. and Oh, S. H., “Modeling of Monolith Reactor Washcoated with CuZSM5 Catalyst for Removing NO from Diesel Engine by Urea,” Ind. Eng. Chem. Res., 45(15), 5258-5267(2006).
15. Ferri, D., Newton, M. A., Di Michiel, M., Yoon, S., Chiarello, G. L., Marchionni, V. and Gieshoff, J., “Synchrotron High Energy X-ray Methods Coupled to Phase Sensitive Analysis to Characterize Aging of Solid Catalysts with Enhanced Sensitivity,” Phys. Chem.Chem. Phys., 15(22), 8629-8639(2013).
16. Hodonj, D., Umemoto, K., Terasawa, M., Yu, Z., Wagner, U., Mori, T. and Lott, P., “Periodic Operation of Three-Way Catalysts: From Synthetic Gas Bench Testing to Real-World Engine Performance,” Ind. Eng. Chem. Res., 64(16), 8143-8155(2025).
17. González-Velasco, J. R., Botas, J. A., González-Marcos, J. A. and Gutiérrez-Ortiz, M. A., “Influence of Water and Hydrocarbon Processed in Feedstream on the Three-way Behaviour of Plati- num-alumina Catalysts,” Appl. Catal. B, 12, 61(1997).
18. Wang, W., Wang, L., Zheng, Z., Zhou, Z., Li, S., Wang, J., and Chen, Y., “Effect of Pd Chemical States on Three-way Catalytic Reaction and C H Total Combustion Reaction in Pd/CeO -ZrO -Al O
38
2 223
catalysts,” Fuel, 372, 132052(2024).
19. Zhao, Y., Wang, W., Yin, X., Wang, L., Li, S., Wang, J. and Chen, Y., “Engineering Excellent Pd/CeO2-ZrO2-Al2O3 Catalyst with Abun- dant Oxygen Vacancies by Pr Surface Modification for Eliminating NO and C3H8,” J. Alloys Compd., 938, 168585(2023).
20. Deng, J., Chen, Y., Li, M., Li, S., Jiao, Y., Wang, J. and Chen, Y., “Formation of Partial κ-Ce Zr O Phase and Its Promotion on
228
the Supported Pd-only Three-way Catalysts,” Mater. Res. Bull., 141, 111341(2021).
21. P. Nevalainen, N.M. Kinnunen, A. Kirveslahti, K. Kallinen, T. Maunula, M. Keenan, and M. Suvanto: “Formation of NH3 and N2O in a Modern Natural Gas Three-way Catalyst Designed for Heavy-duty Vehicles: the Effects of Simulated Exhaust Gas Composi- tion and Ageing,” Appl. Catal. A, 552, 30-37(2018).
22. Ma, L. P., Bart, H. J., Ning, P., Zhang, A., Wu, G. and Zengzang, Z., “Kinetic Study of Threeway Catalyst of Automotive Exhaust Gas: Modeling and Application,” Chem. Eng. J., 155(1-2), 241- 247(2009).
23. You, R., Li, Z., Cao, T., Nan, B., Si, R. and Huang, W., “Synthesis in a Glovebox: Utilizing Surface Oxygen Vacancies to Enhance the Atomic Dispersion of Palladium on Ceria for Carbon Mon- oxide Oxidation and Propane Combustion,” ACS Appl. Nano Mater., 1(9), 4988-4997(2018).
24. Hu, Z., Liu, X., Meng, D., Guo, Y., Guo, Y. and Lu, G., “Effect of Ceria Crystal Plane on the Physicochemical and Catalytic Prop- erties of Pd/ceria for CO and Propane Oxidation,” ACS Catal., 6(4), 2265-2279(2016).
25. Shinde, V. M. and Madras, G., “Water Gas Shift Reaction Over Multi-component Ceria Catalysts,” Appl. Catal. B, 123, 367-378
(2012).
26. Zabilskiy, M., Djinović, P., Tchernychova, E. and Pintar, A., “N2O Decomposition over CuO/CeO2 Catalyst: New Insights Into Reac- tion Mechanism and Inhibiting Action of H2O and NO by Operando Techniques,” Appl. Catal. B, 197, 146-158(2016).27. Lan, L., Huang, X., Zhou, W., Li, H., Xiang, J., Chen, S. and Chen, Y., “Development of a Thermally Stable Pt Catalyst by Redisper- sion Between CeO2 and Al2O3”, RSC Adv., 11(12), 7015-7024(2021).
28. Kim, D. Y., Bae, W. B., Byun, S. W., Kim, Y. J., Yoon, D. Y., Jung,
C. and Kang, S. B., “Pt Substitution in Pd/Rh Three-way Catalyst for Improved Emission Control,” Korean J. Chem. Eng., 40(7), 1606-1615(2023).
29. Machida, M., Fujiwara, A., Yoshida, H., Ohyama, J., Asakura, H., Hosokawa, S. and Iwachido, K., “Deactivation Mechanism of Pd/CeO2–ZrO2 Three-way Catalysts Analyzed By Chassis- dynamometer Tests and In Situ Diffuse Reflectance Spectros-copy,” ACS Catal., 9(7), 6415-6424(2019).
30. Fujiwara, A., Tsurunari, Y., Yoshida, H., Ohyama, J., Yamada, T., Haneda, M. and Machida, M., “Thermal Deactivation of Pd/CeO2– ZrO2 Three-way Catalysts During Real Engine Aging: Analysis by a Surface Plus Peripheral Site Model,” ACS omega, 5(44), 28897-28906(2020).
