Effect of the Amount of Pt Loading on the Oxygen Storage Capacity of Ceria-Zirconia Solid Solution

Abstract

à/ZAWRjAÅnÌÌ_f \ÉyÚ·àSÊÌe¿ {c¾FERºÀbE]zìpvEEÇYEcÓ«ME·äNME òEY³( )Lc¤G}¤ºC4801192 ¤m §·vè¬As an important oxygen storage material, ceriazirconia solid solution is widely used in automotive threeway catalysts. For the CeZr solid solution being usually used with a noble metal, the evaluation of oxygen storage capacity (OSC) should be conducted with the CeZr solid solution loaded with a noble metal. The measured OSC of noblemetalloaded CeZr solid solution consists of two parts: the stored oxygen within the solid solu tion itself and the adsorbed oxygen on the loaded noble metal particles. Therefore, it is very necessary to clarify the influence of metal loading on the measured OSC in order to ascertain the exact OSC of the solid solution it self. In this research, the authors attempted to clarify the above issues by characterizing the OSC performance of CeZr solid solutions with platinum (Pt) loading from 0.000110 mass÷. We found that increasing the amount of Pt loading increases the oxygen storage and release rates and that increasing the temperature also increases the oxygen storage rate, although the oxygen release rate is not affected by increasing the temperature. The apparent OSC reached saturation over a certain amount of Pt loading and temperature. The saturated OSC increased with increasing temperature.

Development of Exhaust Catalyst

“…The molar fractions of trivalent Ce ions of CeO2, X/2, at 500°C in fuel-rich atmosphere, after durability test at 900 and 1200°C were 0.01 and 0.002, respectively, in the study by present authors [ 13]. However, molar fraction of trivalent Ce ions is only a small amount in the total Ce ions.…”

Development of exhaust catalyst

“…The molar fractions of trivalent Ce ions of CeO 2 , X/2, at 500ЊC in fuel-rich atmosphere, after durability test at 900 and 1200ЊC were 0.01 and 0.002, respectively, in the study by present authors [13]. However, molar fraction of trivalent Ce ions is only a small amount in the total Ce ions.…”

Flame-Made Pt/Ceria/Zirconia for Low-Temperature Oxygen Exchange

“…The continuous increase of low-temperature activity at low Pt loading is consistent with earlier investigations. [29][30][31] In terms of loading or OEC onset, flame-made or precipitated materials behaved similarly during the first test run. Thermal Stability.…”

“…These observations are in line with investigations by Suda et al on ceria-zirconia with increasing Pt loading, where a similar saturation could be observed. 31…”