Identification of refractory zirconia from catalytic converters in dust: An emerging pollutant in urban environments

Meza-Figueroa, Diana; Pedroza‐Montero, M.; Barboza‐Flores, M.; Navarro-Espinoza, Sofía; Ruiz-Torres, R.; Robles-Morúa, A.; Romero, Francisco Martín; Schiavo, Benedetto; González-Grijalva, Belem; Acosta-Elías, Mónica; Mendoza-Córdova, A.

doi:10.1016/j.scitotenv.2020.143384

Cited by 11 publications

(20 citation statements)

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“…Thus, the ZrO 2 separates as nano-and microparticles [14], while the Ce is retained in the TWC, forming an Al x Ce 1−x O 2 composite (sample C-TWC) [7]. This information explains why Zr is found in higher amounts in environmental samples when compared to Ce abundance in the same samples [14]. In addition, SiO 2, Al 2 O 3 and MgO (cordierite components) increase in the B-TWC sample.…”

Section: Chemical and Mineralogical Compositionmentioning

confidence: 96%

“…The addition of ZrO2 improves thermal stabili inhibits the reaction of CeO2 with the alumina substrate [7]. Thus, the ZrO2 separ nano-and microparticles [14], while the Ce is retained in the TWC, forming an AlxC Ce content also diminishes in the moderately used device, but in sample C-TWC, its concentration increases compared to B-TWC. This fact is related to the separation of ZrO 2 and CeO 2 phases.…”

Section: Chemical and Mineralogical Compositionmentioning

confidence: 99%

“…This fact is related to the separation of ZrO 2 and CeO 2 phases. The ZrO 2 escapes from the Ce x Zr 1−x O 2 solid solution while CeO 2 keeps trapped in the Al 2 O 3 layer [14,27]. The addition of ZrO 2 improves thermal stability and inhibits the reaction of CeO 2 with the alumina substrate [7].…”

Section: Chemical and Mineralogical Compositionmentioning

confidence: 99%

“…The addition of ZrO 2 improves thermal stability and inhibits the reaction of CeO 2 with the alumina substrate [7]. Thus, the ZrO 2 separates as nano-and microparticles [14], while the Ce is retained in the TWC, forming an Al x Ce 1−x O 2 composite (sample C-TWC) [7]. This information explains why Zr is found in higher amounts in environmental samples when compared to Ce abundance in the same samples [14].…”

Section: Chemical and Mineralogical Compositionmentioning

confidence: 99%

“…Despite the environmental benefits attributed to the TWC, some studies report the release of Pt, Pd and Rh to the environment from this device [11,12]. Moreover, the vehicle's exhaust system is considered the primary source of those pollutants in urban areas [13], including CeO 2 -ZrO 2 micro and nanoparticles (NPs) [14]. However, neither the mechanism of particle release nor the indicators related to transformations within TWC have been addressed.…”

Section: Introductionmentioning

confidence: 99%

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Release of Nanoparticles in the Environment and Catalytic Converters Ageing

et al. 2021

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A Three-Way Catalyst (TWC) contains a cordierite ceramic monolith coated with a layer of Al2O3, CexZr1−xO2 and platinoids mixture. Under standard operation, the platinoid concentration decreases, exposing the remaining washcoat structure. After that particle release stage, the sintering process follows where the crystalline CexZr1−xO2 solution is broken and begins to separate into ZrO2 and CeO2 phases. ZrO2 is released to the environment as micro and nanoparticles, while a small amount of CeO2 generates a new AlxCe1−xO2 composite. The main effect of Ce capture is the growth in the size of the polycrystal structure from 86.13 ± 16.58 nm to 225.35 ± 69.51 nm. Moreover, a transformation of cordierite to mullite was identified by XRD analysis. Raman spectra showed that the oxygen vacancies (Vö) concentration decreased as CexZr1−xO2 phases separation occurred. The SEM-EDS revealed the incorporation of new spurious elements and microfractures favouring the detachment of the TWC support structure. The release of ultrafine particles is a consequence of catalytic devices overusing. The emission of refractory micro to nanocrystals to the atmosphere may represent an emerging public health issue underlining the importance of implementing strict worldwide regulations on regular TWCs replacement.

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Section: Chemical and Mineralogical Compositionmentioning

confidence: 96%

Section: Chemical and Mineralogical Compositionmentioning

confidence: 99%