To reveal the effect of ceria particle size on dispersion and structure of supported Pt catalysts during preparation, activation, and reaction testing, a unique CeO₂/Al₂O₃ support (CA−c) with smaller CeO₂ particle size and more surface defects was prepared using a colloidal CeO₂ precursor, comparing with a conventional CeO₂/Al₂O₃ support (CA−n) using cerium nitrate as precursor. More atomically dispersed Pt and abundant Pt−O−Ce structures were observed in the Pt/CA−c catalyst than in the Pt/CA−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/CA−c. We found that smaller Pt clusters with more active ionic Pt sites were generated on the activated Pt/CA−c catalyst, while agglomerated larger Pt particles with more metallic sites were formed on the activated Pt/CA−n. The facile formation of Ce³⁺ was also indicative of more active metal‐support interfaces in the activated Pt/CA−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.

中文翻译：

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调整单原子Pt1-CeO2催化剂以有效进行CO和C3H6氧化：二氧化铈对Pt结构演变的尺寸影响

为了揭示二氧化铈粒度对制备，活化和反应测试过程中负载的Pt催化剂的分散和结构的影响，一种独特的CeO ₂ / Al ₂ O ₃载体（CA-c）具有较小的CeO ₂粒度和更多的表面缺陷与常规的CeO ₂ / Al ₂ O ₃相比，使用胶态CeO ₂前体制备硝酸铈作为前体的载体（CA-n）。与在Pt / CA-n催化剂中相比，在Pt / CA-c催化剂中观察到更多的原子分散的Pt和丰富的Pt-O-Ce结构。如果在反应之前在400°C下被10％氢活化，则两种母体催化剂的催化CO氧化活性都会得到显着提高。在两种代表性催化剂之间，对于Pt / CA-c，活化后活性增强的程度更为明显。我们发现，在活化的Pt / CA-c催化剂上生成了具有更多活性离子Pt位置的较小的Pt团簇，而在活化的Pt / CA-n上形成了具有更多金属位点的较大的Pt团聚体。Ce ³⁺的容易形成也表明活化的Pt / CA-c催化剂中有更多的活性金属-载体界面。这些结果凸显了调节二氧化铈载体颗粒以实现可控锚固和随后激活Pt单原子以进行低温CO氧化反应的重要性。