(484g) Measurement of the Oxygen Storage Capacity and Its Role in the Catalytic Oxidation

CeO₂, thanks to its unique redox property of oxygen storage and release under lean and rich conditions, respectively, has been widely used as the catalyst support component. This property of oxygen storage and release can usually be quantitatively measured, called the oxygen storage capacity (OSC), via a reduction method using different techniques. The amount of OSC measured depends on the type of reducing agent and the technique used. Furthermore, the OSC is also influenced by the synthesis method of CeO₂, the modification by other elements like ZrO₂, the physical and geometric properties, and the metal supported on CeO₂-based materials. On the other hand, it is well accepted that the catalytic activity benefits from the unique characteristic of oxygen storage and release for reactions carried out over the CeO₂-based catalysts. Unfortunately, the significant enhancement of catalytic activity is still poorly correlated by the OSC, or the role of OSC in favoring the catalytic reaction is still poorly understood. We establish the measurement of OSC by comparing the use of different reducing agents (CO and H₂) and the use of different techniques (TCD and TGA). The effects of synthesis method, high temperature aging, precious metal loading, and the structure modification by ZrO₂ (i.e. CZO) and other stabilizer elements on CeO₂ have been also investigated. The OSC measured by different methods and the influencing factors are analyzed with emphasis on to the catalytic activity like CO oxidation for the objectives to establish a correlation between OSC and catalytic activity.