Tailoring the Local Environment of Platinum in Single-Atom Pt₁ /CeO₂ Catalysts for Robust Low-Temperature CO...

A single-atom Pt₁ /CeO₂ catalyst formed by atom trapping (AT, 800 °C in air) shows excellent thermal stability but is inactive for CO oxidation at low temperatures owing to over-stabilization of Pt²⁺ in a highly symmetric square-planar Pt₁ O₄ coordination environment. Reductive activation to form Pt nanoparticles (NPs) results in enhanced activity; however, the NPs are easily oxidized, leading to drastic activity loss. Herein we show that tailoring the local environment of isolated Pt²⁺ by thermal-shock (TS) synthesis leads to a highly active and thermally stable Pt₁ /CeO₂ catalyst. Ultrafast shockwaves (>1200 °C) in an inert atmosphere induced surface reconstruction of CeO₂ to generate Pt single atoms in an asymmetric Pt₁ O₄ configuration. Owing to this unique coordination, Pt₁ ^δ+ in a partially reduced state dynamically evolves during CO oxidation, resulting in exceptional low-temperature performance. CO oxidation reactivity on the Pt₁ /CeO₂ _TS catalyst was retained under oxidizing conditions.