Enhancing the low-temperature performance of Pt-based three-way catalysts using CeO2(core)@ZrO2(shell) supports

Abstract

Developing robust Pt/CeO₂-based three-way catalysts (TWCs) with enhanced oxygen buffering capability and low-temperature activity is highly desirable. In this study, a new TWC family, Pt/(1 − x)CeO₂(core)@xZrO₂(shell) (where x = 0–0.5), was prepared and evaluated at degreened (DG) and hydrothermally aged (HTA) states. Incorporation of 0.1 molar concentration of ZrO₂ resulted in a decreased temperature that 50% (T₅₀) (CO: 167 °C, THCs: 218 °C, NO: 228 °C) and 90% (T₉₀) (CO: 207 °C, THCs: 237 °C, NO: 244 °C) conversions achieved over HTA 1.8 wt% Pt/0.9CeO₂@0.1ZrO₂ compared to the HTA 1.8 wt% Pt/CeO₂ sphere (CO: T_50,90 = 179, 222 °C, THCs: 234, 252 °C, NO_x: 240, 260 °C). An enhanced oxygen storage capacity and oxygen release rate were observed over Pt/0.9CeO₂@0.1ZrO₂ compared to the Pt/CeO₂ sphere. Increasing the ZrO₂ molar concentration to values greater than 0.2 resulted in increased T₅₀s (224, 265 274 °C) and T₉₀s (251, 289, 292 °C) for CO, THCs, and NO_x, respectively, over 1.8 wt.% Pt/0.5CeO₂@0.5ZrO₂. Overall, this work highlights the potential of forming a ZrO₂ shell on CeO₂ spheres as a support for TWC applications.