Activation of surface lattice oxygen in single-atom Pt/CeO₂ for low-temperature CO oxidation

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 100°C 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 750°C) 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 800°C in oxidizing environments.