Deactivation of real three way catalysts by CePO4 formation

Larese, C.

doi:10.1016/s0926-3373(02)00161-3

Cited by 88 publications

(36 citation statements)

References 34 publications

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“…About 35 g of ZDDP (Lubrizol, Wickliffe, OH, USA) or IL (synthesized as described elsewhere [12][13][14][15]) was used in each catalyst aging evaluation to simulate the maximum lifetime consumption of lubricant anti-wear additive in a modern automotive engine (90 mg/km) . This consumption rate is conservatively based on the high end of "normal" oil consumption data from vehicle operation using the standard road cycle [20]. The estimate also assumes 1% additive concentration in the lubricant.…”

Section: Accelerated Catalyst Aging Systemmentioning

confidence: 99%

Impact of Lubricant Additives on thePhysicochemical Properties and Activity of Three‐Way Catalysts

et al. 2016

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Abstract:As alternative lubricant anti-wear additives are sought to reduce friction and improve overall fuel economy, it is important that these additives are also compatible with current emissions control catalysts. In the present work, an oil-miscible phosphorous-containing ionic liquid (IL), trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate ([P 66614 ][DEHP]), is evaluated for its impact on three-way catalysts (TWC) and benchmarked against the industry standard zinc-dialkyl-dithio-phosphate (ZDDP). The TWCs are aged in different scenarios: neat gasoline (no-additive, or NA), gasoline+ZDDP, and gasoline+IL. The aged samples, along with the as-received TWC, are characterized through various analytical techniques including catalyst reactivity evaluation in a bench-flow reactor. The temperatures of 50% conversion (T50) for the ZDDP-aged TWCs increased by 30, 24, and 25˝C for NO, CO, and C 3 H 6 , respectively, compared to the no-additive case. Although the IL-aged TWC also increased in T50 for CO and C 3 H 6 , it was notably less than ZDDP, 7 and 9˝C, respectively. Additionally, the IL-aged samples had higher water-gas-shift reactivity and oxygen storage capacity than the ZDDP-aged TWC. Characterization of the aged samples indicated the predominant presence of CePO 4 in the ZDDP-aged TWC aged by ZDDP, while its formation was retarded in the case of IL where higher levels of AlPO 4 is observed. Thus, results in this work indicate that the phosphonium-phosphate IL potentially has less adverse impact on TWC than ZDDP.

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Section: Accelerated Catalyst Aging Systemmentioning

confidence: 99%

Impact of Lubricant Additives on thePhysicochemical Properties and Activity of Three‐Way Catalysts

et al. 2016

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“…Most of the peaks were attributed to the cordierite that is the material of the monolith. Its diffraction lines can be found in the literature (Larese et al [14] and Martín et al [15]). Indeed, it was not possible to observe any ␥-Al 2 O 3 peaks in the fresh catalyst diffractogram.…”

Section: Resultsmentioning

confidence: 88%

“…According to Larese et al [14], the reaction between Ce +3 and alumina leading to cerium aluminate formation was not found when using Ce/Zr mixed oxides in the place of CeO 2 , since the insertion of Zr into the cerium oxide lattice minimizes this interaction. Indeed, Yue et al [24], who prepared Ce x Zr 1−x O 2 /Al 2 O 3 with different Zr contents, did not observe CeAlO 3 formation in samples calcined at 1000 • C for 2 h. Fig.…”

Section: Resultsmentioning

confidence: 99%

Thermal deactivation of Pt/Rh commercial automotive catalysts

Fernandes

Scofield

Neto

et al. 2010

Chemical Engineering Journal

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“…The cause of converters losing their OSC has been well investigated (Angove et al, 2000;Larese et al, 2003;Liu et al, 1993;Uy et al, 2003;Beck et al, 1994a;Beck et al, 1997;Beck et al, 1994b). High temperature sintering causes collapse of the wash coat with the CeO 2 -ZrO 2 oxide mixture, so that the most active sites for the reaction Ce 2 O 3 + O 2 ↔ CeO 2 (Angove et al, 2000;Larese et al, 2003) are lost. At high temperature, the interaction between ceria and alumina leads to the formation of CeAlO 3 .…”

Section: Discussionmentioning

confidence: 99%

Performance Study of 48 Road-Aged Commercial Three Way Catalytic Converters

Chan

Ljungström

2006

Water Air Soil Pollut

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48 commercial three-way catalytic converters (TWC) aged on-road were investigated. The results show that there was no significant impact of aging on light off temperatures for CO, HC, and NO up to 120 000 km. Above 120 000 km, the light off temperatures in general increased. The steady state conversions for CO and HC are not significantly affected by aging. However, the steady state conversion of NO is decreased with increased mileage at the conditions studied. The impact of aging on oxygen storage capacity (OSC) of the converters was studied by propene pulse experiments. A trend of decreased pulse conversion was noted above 120 000 km. OSC and NOconversion showed considerable difference between individuals with similar mileage. A number of high-mileage units perform well while a few low-mileage converters appear to be next to destroyed. The surface characterization shows that the main cause of deactivation was loss of specific surface, both of washcoat and precious metals. This is most likely due to exposure to high temperatures. Poisoning elements, typically phosphorus, lead, sulphur and calcium, are found on the catalysts surface.

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Deactivation of real three way catalysts by CePO4 formation

Cited by 88 publications

References 34 publications

Impact of Lubricant Additives on thePhysicochemical Properties and Activity of Three‐Way Catalysts

Impact of Lubricant Additives on thePhysicochemical Properties and Activity of Three‐Way Catalysts

Thermal deactivation of Pt/Rh commercial automotive catalysts

Performance Study of 48 Road-Aged Commercial Three Way Catalytic Converters

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