The Role of Zirconium in Novel Three-Way Catalysts

Muβmann, L.; Lindner, D.; Lox, E.S.; Yperen, R. van; Kreuzer, Thomas; Mitsushima, Isao; Taniguchi, Satoshi; Garr, G.

doi:10.4271/970465

Cited by 7 publications

(5 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Yao and Yu Yao [14] first proposed the H 2 or CO pulse injection method that allows the measurement of OSC of catalytic materials, and Sakamoto et al [15] studied the OSC by means of TG, which both belong to static studies of the reaction. In contrast, there is a dynamic study of oxygen storage capacity (DOSC) [16][17][18][19], which is OSC measurement at a continuous oxidation and reduction state by the few seconds time-scale. It is obvious that DOSC measurement is more important for the development of oxygen storage materials for practical use, since it can simulate the real operating conditions that the exhaust gas composition rapidly oscillates between reducing and oxidizing environment, although it is very difficult to apply it to actual exhaust systems.…”

Section: Introductionmentioning

confidence: 99%

Dynamic oxygen storage and release over Mn0.1Ce0.9Ox and Mn0.1Ce0.6Zr0.3Ox complex compounds and structural characterization

Jia

Shen

Hao

et al. 2008

Journal of Alloys and Compounds

View full text Add to dashboard Cite

The dynamic oxygen storage capacity (DOSC) and rate (DOSR) over Mn 0.1 Ce 0.9 O x and Mn 0.1 Ce 0.6 Zr 0.3 O x prepared by sol-gel method were investigated. The results show that Ce-based compounds containing Mn oxides with variable valences contribute to the majority of DOSC and DOSR performances at low temperature, and the DOSC and DOSR of Mn-Ce-O can be enhanced by the Zr addition at high temperature. Both materials were characterized by XRD, BET, Raman, TPR, EPR and XPS. XRD and Raman results indicate that Mn 0.1 Ce 0.9 O x and Mn 0.1 Ce 0.6 Zr 0.3 O x are characterized with the fluorite-type cubic structure similar to CeO 2 , and furthermore the thermal stability of M-Ce-O materials is improved by the introduction of some Zr atoms. EPR researches reveal that there are three types of Mn 2+ species: isolated Mn 2+ substituting for Ce 4+ ions in the lattice with a cubic symmetry, ones in defect with a noncubic symmetry and at the surface of samples. From XPS, it can be concluded that Mn 2+ /Mn 3+ redox couples exist on the surface of Mn 0.1 Ce 0.9 O x and Mn 0.1 Ce 0.6 Zr 0.3 O x samples.

show abstract

Section: Introductionmentioning

confidence: 99%

Dynamic oxygen storage and release over Mn0.1Ce0.9Ox and Mn0.1Ce0.6Zr0.3Ox complex compounds and structural characterization

Jia

Shen

Hao

et al. 2008

Journal of Alloys and Compounds

View full text Add to dashboard Cite

show abstract

“…The dynamic of oxygen storage capacity (DOSC) means that OSC measurement is at a continuous oxidation and reduction state by the few seconds time-scale [18][19][20][21]. In early report [22], the dynamic of oxygen storage rate (DOSR) defined as the amount of oxygen stored and released in the first second of every oscillation cycle was acted as a method to characterize oxygen storage material performance.…”

Section: Introductionmentioning

confidence: 99%

Dynamic oxygen storage and release over Cu0.1Ce0.9Ox and Cu0.1Ce0.6Zr0.3Ox complex compounds and structural characterization

Shen

Wang

Gu³

2009

Journal of Alloys and Compounds

View full text Add to dashboard Cite

“…For the technical application, it is essential to control the storage level θTWC of the oxygen storage component. To effectively reduce raw emissions during operation, the fully oxidized and reduced states must be avoided, as they are associated with emission breakthroughs [18].…”

Section: Introductionmentioning

confidence: 99%

Microwave-Based State Diagnosis of Three-Way Catalysts: Impact Factors and Application Recommendations

Steiner,

Malashchuk,

Kubinski

et al. 2024

Sensors

View full text Add to dashboard Cite

This study reassesses an overview of the potential of the radio frequency (RF)-based state diagnostics of three-way catalysts (TWC) based on a previous study with an emphasis on the defect chemistry of the catalyst material during reoxidation and reduction. Some data are based on the previous works but are newly processed, and the signal parameters resonant frequency and inverse quality factor are evaluated with respect to applicability. The RF-based method uses electromagnetic resonances in a cavity resonator to provide information on the storage level of the oxygen storage component. The analysis focuses on a holistic investigation and evaluation of the major effects influencing the RF signal during operation. On the one hand, the response to the oxygen storage behavior and the resolution of the measurement method are considered. Therefore, this study merges original data from multiple former publications to provide a comprehensive insight into important measurement effects and their defect chemistry background. On the other hand, the most important cross-sensitivities are discussed and their impact during operation is evaluated. Additionally, the effect of catalyst aging is analyzed. The effects are presented separately for the two resonant parameters: resonant frequency and (unloaded) quality factor. Overall, the data suggest that the quality factor has a way higher signal quality at low temperatures (<400 °C) and the resonant frequency is primarily suitable for high operating temperatures. At most operating points, the quality factor is even more robust against interferences such as exhaust gas stoichiometry and water content. Correctly estimating the catalyst temperature is the most important factor for reliable results, which can be achieved by combining the information of both resonant signals. In the end, the data indicate that microwave-based state diagnosis is a powerful system for evaluating the oxygen storage level over the entire operating range of a TWC. As a research tool and in its application, the system can therefore contribute to the improvement of the emission control of future gasoline vehicles.

show abstract

The Role of Zirconium in Novel Three-Way Catalysts

Cited by 7 publications

References 15 publications

Dynamic oxygen storage and release over Mn0.1Ce0.9Ox and Mn0.1Ce0.6Zr0.3Ox complex compounds and structural characterization

Dynamic oxygen storage and release over Mn0.1Ce0.9Ox and Mn0.1Ce0.6Zr0.3Ox complex compounds and structural characterization

Dynamic oxygen storage and release over Cu0.1Ce0.9Ox and Cu0.1Ce0.6Zr0.3Ox complex compounds and structural characterization

Microwave-Based State Diagnosis of Three-Way Catalysts: Impact Factors and Application Recommendations

Contact Info

Product

Resources

About