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Activation of surface lattice oxygen in single-atom Pt/CeO <sub>2</sub> for low-temperature CO oxidation

Lei Nie, Donghai Mei, Haifeng Xiong, Bo Peng, Zhibo Ren, Xavier Isidro Pereira Hernández, Andrew DeLaRiva, Meng Wang, Mark Engelhard, Libor Kovařík,

Science · 2017 · 1.5K citations · 36 references

DOI Full text

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TL;DR

Advanced combustion engines aim to reduce exhaust heat waste, requiring catalysts that operate 100 °C lower than current ones, yet maintaining performance under high loads remains a formidable challenge. The study demonstrates that steam‑activated, atomically dispersed Pt²⁺ on CeO₂ can enable low‑temperature CO oxidation while maintaining hydrothermal stability. Steam treatment creates new active sites on CeO₂ adjacent to Pt²⁺ that enhance reactivity. The resulting active sites remain stable up to 800 °C under oxidizing conditions.

Abstract

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.