研究目的
To study the effect of post deposition heat treatment (post-treatment) conditions on the catalytic performance of Au8 cluster-derived catalysts in benzyl alcohol oxidation.
研究成果
The Au8/TiO2:O2–H2 catalyst showed a significant increase in benzyl alcohol conversion by 30%, suggesting that the heat treatment under the H2 stream changed the nature of the NO3 species present in the gold clusters. NO3 anions were suggested to inhibit the catalytic activity of gold clusters in benzyl alcohol oxidation.
研究不足
The study is limited by the resolution limit of the conventional HRTEM and poor contrast of small clusters over support material, making imaging such small clusters challenging. Additionally, the low gold loading adds difficulty in imaging such small clusters and constructing a statistical histogram.
1：Experimental Design and Method Selection:
The study involved preparing heterogeneous gold catalysts by depositing atomically-precise phosphine-ligated gold clusters, Au8(PPh3)8(NO3)2, onto anatase-phase TiO2 nanoparticles. The catalysts were then calcined under two different conditions: O2 (Au8/TiO2:O2) and O2 followed by H2 (Au8/TiO2:O2–H2) at 200 °C.
2：Sample Selection and Data Sources:
The catalysts were tested in benzyl alcohol oxidation.
3：List of Experimental Equipment and Materials:
High-resolution bright field transmission electron microscopy (HRTEM) imaging was performed using a Philips CM200 TEM operating at 200 kV. UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS) spectra were recorded using a Cintra 404 (GBC Scientific Equipment) spectrophotometer.
4：Experimental Procedures and Operational Workflow:
Catalytic testing was performed in a Teflon liner with benzyl alcohol, anisole as internal standard, methanol as solvent, K2CO3, and catalyst, pressurized with 5 bar of oxygen and heated to 80 °C for 4 h.
5：Data Analysis Methods:
Product mixtures were identified and quantified using a high-performance liquid chromatography (HPLC) Dionex Ultimate 300 system.
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