High-temperature stable hydroxyls tuning the local environment of Pt single atoms for boosting formaldehyde oxidation

Abstract

The relationship between the structure and performance of metal single-atom catalysts remains elusive because it is a challenge to tailor the local environments of single atoms (SAs) while keeping the atomic dispersion. Here, two Pt/CeO₂ catalysts with different Pt coordination environments were prepared at high temperatures, via both atom trapping (Pt₁/CeO₂-AT) and thermal shock (Pt₁/CeO₂-TS), respectively. The Pt SAs in the Pt₁/CeO₂-TS catalyst with an unsymmetrical structure surrounded by stable surface hydroxyls exhibit excellent HCHO oxidation activity. Pt SAs are primarily found at Ce substitution sites in the Pt₁/CeO₂-TS catalyst, which has a Pt₁O₃ configuration with hydroxyls and more active surface lattice oxygen than the Pt₁/CeO₂-AT catalyst. Due to their different coordination and redox properties, Pt₁/CeO₂-TS and Pt₁/CeO₂-AT show different performances in HCHO oxidation (T₁₀₀ of HCHO shifts from 60 to 200 °C), confirming that the catalytic performance of Pt SACs can be tailored by optimizing the local environment via high-temperature stable hydroxyls.