Herein, we report the synthesis of gold (Au)-loaded mesoporous iron oxide (Fe₂O₃) as a catalyst for both CO and NH₃ oxidation. The mesoporous Fe₂O₃ is firstly prepared using polymeric micelles made of an asymmetric triblock copolymer poly(styrene-b-acrylic acid-b-ethylene glycol) (PS-b-PAA-b-PEG). Owing to its unique porous structure and large surface area (87.0 m² g⁻¹), the as-prepared mesoporous Fe₂O₃ can be loaded with a considerably higher amount of Au nanoparticles (Au NPs) (7.9 wt%) compared to the commercial Fe₂O₃ powder (0.8 wt%). Following the Au loading, the mesoporous Fe₂O₃ structure is still well-retained and Au NPs with varying sizes of 3–10 nm are dispersed throughout the mesoporous support. When evaluated for CO oxidation, the Au-loaded mesoporous Fe₂O₃ catalyst shows up to 20% higher CO conversion efficiency compared to the commercial Au/Fe₂O₃ catalyst, especially at lower temperatures (25–150 °C), suggesting the promising potential of this catalyst for low-temperature CO oxidation. Furthermore, the Au-loaded mesoporous Fe₂O₃ catalyst also displays a higher catalytic activity for NH₃ oxidation with a respectable conversion efficiency of 37.4% compared to the commercial Au/Fe₂O₃ catalyst (15.6%) at 200 °C. The significant enhancement in the catalytic performance of the Au-loaded mesoporous Fe₂O₃ catalyst for both CO and NH₃ oxidation may be attributed to the improved dispersion of the Au NPs and enhanced diffusivity of the reactant molecules due to the presence of mesopores and a higher oxygen activation rate contributed by the increased number of active sites, respectively.

中文翻译：

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负载在介孔氧化铁上的金纳米颗粒可增强CO氧化反应

在本文中，我们报道了负载金（Au）的中孔氧化铁（Fe ₂ O ₃）的合成，该催化剂可同时催化CO和NH ₃氧化。中孔的Fe ₂ ö ₃是使用由不对称三嵌段共聚物的聚（苯乙烯-聚合物胶束首先制备b -丙烯酸酸- b -亚乙基二醇）（PS- b -PAA- b -PEG）。由于其独特的多孔结构和较大的表面积（87.0 m ² g ^-1），因此制得的介孔Fe ₂ O ₃与市售的Fe ₂ O ₃粉末（0.8重量％）相比，可向其负载明显更高量的金纳米颗粒（Au NP）（7.9重量％）。在Au负载后，介孔Fe ₂ O ₃结构仍然保持良好，并且大小在3–10 nm的Au NPs分散在整个介孔载体中。当评估CO氧化时，载有Au的中孔Fe ₂ O ₃催化剂与商业化的Au / Fe ₂ O ₃相比，显示出高达20％的CO转化效率催化剂，特别是在较低的温度（25–150°C）下，表明该催化剂在低温CO氧化方面的潜力很大。此外，与市售Au / Fe ₂ O ₃催化剂（15.6％）在200℃相比，Au负载的中孔Fe ₂ O ₃催化剂还显示出更高的NH ₃氧化催化活性，转化效率为37.4％。负载金的介孔Fe ₂ O ₃催化剂对CO和NH ₃的催化性能显着增强 氧化可以归因于由于中孔的存在而导致的Au NPs分散性的改善和反应物分子扩散性的提高，以及由于活性位点数量的增加而导致的较高的氧活化率。