Quantitative and qualitative analysis of two degradation factors on oxygen storage capacity of Pd/CeO₂-ZrO₂ three-way catalysts

Three-way catalyst (TWC) performance degrades when it is exposed to high exhaust gas temperatures. High temperatures increase sintering and thermal aging, which reduce precious-metal catalytic activity and oxygen storage capacity (OSC) in support materials such as CeO₂-ZrO₂ (CZ). The OSC reduction can be attributed to two degradation factors: active-site density (quantitative) and reaction-rate parameters (qualitative). In this work, both factors are demonstrated in experiments, and a new data analysis method is used to develop a high-fidelity TWC model that accounts for surface adsorption/desorption reactions and OSC characteristics. The results of this work include a novel method for analyzing the two degradation factors and an improved TWC model for predicting CO oxidation kinetics. Additionally, the authors introduce the quantitative degradation factor to enhance the catalyst prediction model, enabling it to predict purification performance across fresh, mild, and severe aging levels.