Ag–CoO nanocomposites for gas-phase oxidation of alcohols to aldehydes and ketones: intensified O2 activation at Ag–CoO interfacial sites,Catalysis Science & Technology

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Ag–CoO nanocomposites for gas-phase oxidation of alcohols to aldehydes and ketones: intensified O2 activation at Ag–CoO interfacial sites
Catalysis Science & Technology ( IF 4.4 ) Pub Date : 2020-10-19 , DOI: 10.1039/d0cy01613f
Kun Liu _{1,

2,

3,

4,

5} , Yichen Zhao _{1,

2,

3,

4,

5} , Jiale Wang _{1,

2,

3,

4,

5} , Qingsong Xue _{5,

6,

7,

8,

9} , Guofeng Zhao _{5,

6,

7,

8,

9}

Affiliation

The fabrication of qualified catalysts is a key issue to implement gas-phase aerobic alcohol oxidation but necessarily requires understanding the structures of catalytic active sites and the supply of active oxygen species. Herein, we present one example of the Ag–CoO/Ti- powder catalyst for gas-phase benzyl alcohol aerobic oxidation. The first interesting observation is that the Ag–Co₃O₄ ensembles on the fresh catalyst could be transformed into Ag–CoO due to the presence of reductive benzyl alcohol. The preferred catalyst with 3 wt% Ag and 3 wt% CoO exhibits 93% benzyl alcohol conversion and 99% benzaldehyde selectivity at a weight hourly space velocity of 20 h⁻¹ and a temperature of 240 °C. The structures of Ag–CoO ensembles and oxygen species supply were probed and identified by electron microscopy and other spectroscopy techniques in combination with temperature-programmed thermal analyses, pulse experiments, and kinetic studies. In nature, the oxygen species is generated at the Ag–CoO interfacial sites in the form of atomic oxygen with appropriate chemisorption strength on these sites to achieve a high oxidation activity of benzyl alcohol. Moreover, the Co₃O₄ ↔ CoO cycle is promoted by Ag at low temperature such as 240 °C to endow the Ag–CoO ensembles with excellent catalytic performance.

中文翻译：

用于将醇气相氧化为醛和酮的Ag-CoO纳米复合材料：Ag-CoO界面处的O2活化增强

合格催化剂的制造是实施气相好氧醇氧化的关键问题，但必须要求了解催化活性位的结构和活性氧的供应。在这里，我们提供一个用于气相苯甲醇好氧氧化的Ag-CoO / Ti-粉末催化剂的例子。第一个有趣的观察结果是，由于存在还原性苯甲醇，新鲜催化剂上的Ag-Co ₃ O ₄团簇可以转化为Ag-CoO。具有3wt％的Ag和3wt％的CoO的优选催化剂在20h ^-1的重时空速下表现出93％的苄醇转化率和99％的苯甲醛选择性。温度为240°C。通过电子显微镜和其他光谱技术，结合程序升温的热分析，脉冲实验和动力学研究，探测和鉴定了Ag-CoO团簇的结构和氧的供应。在自然界中，氧以原子氧的形式在Ag-CoO界面位点产生，这些位点具有适当的化学吸附强度，可实现苯甲醇的高氧化活性。此外，将Co ₃ ö ₄ ↔CoO的周期是由银在低温下促进如240℃以赋予所述Ag-CoO的合奏具有优异的催化性能。

更新日期：2020-11-09

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