(512e) Templated Encapsulation of Pt Nanoparticles in Mixed Porous Oxides Promotes Low Temperature Activity and High Temperature Stability for Emission Control Catalysts

Modern emission control catalysts face the harsh environment present in post reacted combustion engine outflow, with extreme temperature fluctuations up to 1100 ℃. To achieve low-temperature activity, mixed oxide supports show promising opportunities for supported noble metal catalysts. We developed a method of encapsulating metal particles inside porous alumina layers that resulted in highly stable noble metal catalysts, but the activity could be improved further by using mixed oxide layers. We here discuss the use of mixed manganese oxide-alumina encapsulating layers as a support to achieve the most desirable catalytic characteristics. The synergistic effects of alumina and manganese oxide together have been demonstrated to increase post-aging activity, guaranteeing thermal stability and avoiding Pt phase sintering at temperatures in excess of 800 C. Investigation of this system revealed the complex nature of manganese oxide as sensitive to changing oxidation state and its role as an active oxygen phase. This material therefore shows extremely promising results to achieve more stable and active emission control catalysts, while simultaneously reducing platinum consumption in catalyst production.