Tuning Single‐atom Pt₁−CeO₂ Catalyst for Efficient CO and C₃H₆ Oxidation: Size Effect of Ceria on Pt Structural Evolution

Abstract

To reveal the effect of ceria particle size on dispersion and structure of supported Pt catalysts during preparation, activation, and reaction testing, a unique CeO 2 / Al 2 O 3 support (CAÀ c) with smaller CeO 2 particle size and more surface defects was prepared using a colloidal CeO 2 precursor, comparing with a conventional CeO 2 /Al 2 O 3 support (CAÀ n) using cerium nitrate as precursor. More atomically dispersed Pt and abundant PtÀ OÀ Ce structures were observed in the Pt/CAÀ c catalyst than in the Pt/CAÀ n catalyst. Both parent catalysts received significant enhancement on their catalytic CO oxidation activities if activated by 10% hydrogen at 400°C before reaction. Between the two representative catalysts, the extent of activity enhancement upon activation was more pronounced for Pt/CAÀ c. We found that smaller Pt clusters with more active ionic Pt sites were generated on the activated Pt/CAÀ c catalyst, while agglomerated larger Pt particles with more metallic sites were formed on the activated Pt/CAÀ n. The facile formation of Ce 3 + was also indicative of more active metal-support interfaces in the activated Pt/CAÀ c catalyst. These results highlight the importance of regulating ceria support particles to enable a controlled anchoring and subsequent activation of Pt single atoms for low-temperature CO oxidation reaction.

Fine-tuned local coordination environment of Pt single atoms on ceria controls catalytic reactivity

“…The H 2 -consumption peaks centered around 150 °C could be attributed to the reduction of Pt–O–Ce structure, while the H 2 -consumption peaks at ca . 420 and 785 °C could be ascribed to the reduction of surface Ce 4+ species and bulk CeO 2 , respectively 41 . Interestingly, as the calcination temperature increased from 550 to 800 °C, the H 2 -consumption peak assigned to the reduction of Pt–O–Ce structure shifted to higher temperatures (126 °C → 173 °C) with enhanced intensity, indicating the different strength of Pt–O–Ce interaction as well as the different locations of Pt single atoms on Pt/CeO 2 -X catalysts.…”

Evaluation of Manganese Oxide Octahedral Molecular Sieves for CO and C3H6 Oxidation at Diesel Exhaust Conditions

“…Interesting, in the presence of C 3 H 6 , MnO(3 × 3) exhibited much better CO oxidation activity than MnO(2 × 2) and MnO(1 × 1), which was quite different from the results of CO oxidation without C 3 H 6 in the reactant. The catalytic performance of some typical catalysts for the oxidation of CO and propylene were listed in Table 2 (Seo et al, 2021;Li et al, 2019;Ma et al, 2018;Li et al, 2021;Hazlett et al, 2017;Wang et al, 2019;Rida et al, 2006;Tan et al, 2020;Liu et al, 2020;Březina et al, 2020). It was seen that noble metal catalysts had outstanding low-temperature activity below 250°C, while the catalytic activity of transition metal catalysts was generally lower than that of noble metal catalysts.…”

Construction of cerium-based oxide catalysts with abundant defects/vacancies and their application to catalytic elimination of air pollutants

“…Compared with palladium and rhodium, platinum has a lower price, higher abundance, and good catalytic activity, and platinum-based compounds are regarded as promising catalysts for CO oxidation. 92 The oxidation of CO over Pt/CeO 2 follows the MvK mechanism, where the CO adsorbed on platinum reacts with the active lattice oxygen provided by CeO 2 , as represented by eqn (5): 93,94 2Ce 4+ + O 2− + CO–Pt δ + → 2Ce 3+ + V o + Pt δ + + CO 2 …”