Activation of surface lattice oxygen in single atom Pt/CeO2 for low temperature CO oxidation
Stable catalysts through steaming The lifetime of catalysts that convert automotive exhaust pollutants can be increased by lowering their operating temperature, which helps to prevent deactivation caused by the active metal atoms agglomerating into larger, less active particles. Nie et al. show that a thermally stable catalyst, atomically dispersed Pt2+ on CeO2, can become active for CO oxidation at 150degC after steam treatment at 750degC. In studies with simulated vehicle exhaust, this catalyst treatment also improves its oxidation activity for other exhaust components such as hydrocarbons. Science, this issue p. 1419 Steam treatment at 750degC transforms single Pt2+ ions on CeO2 into a CO oxidation catalyst active at low temperatures. To improve fuel efficiency, advanced combustion engines are being designed to minimize the amount of heat wasted in the exhaust. Hence, future generations of catalysts must perform at temperatures that are 100degC lower than current exhaust treatment catalysts. Achieving low temperature activity, while surviving the harsh conditions encountered at high engine loads, remains a formidable challenge. In this study, we demonstrate how atomically dispersed ionic platinum (Pt2+ on ceria (CeO2) which is already thermally stable, can be activated via steam treatment (at 750degC) to simultaneously achieve the goals of low temperature carbon monoxide (CO) oxidation activity while providing outstanding hydrothermal stability. A new type of active site is created on CeO2 in the vicinity of Pt2+ which provides the improved reactivity. These active sites are stable up to 800degC in oxidizing environments.
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