Ti掺杂CeO2纳米片负载Pd催化剂催化醇类氧化:界面位点的催化作用

Ti doped CeO2 nanosheets supported Pd catalyst for alcohol oxidation: Catalysis of interfacial sites

  • 摘要: 本研究通过Ti掺杂以及改变Ti的掺杂量可控制备了表面氧空位浓度不同的CeO2纳米片,将其作为载体负载Pd物种后研究其醇类氧化性能。X射线光电子能谱、拉曼光谱以及X射线吸收谱的表征结果显示,CeO2表面氧空位浓度和Pd2 + 的比例正向相关。醇类氧化评价结果和构效关系研究显示,Pd2 + 比例和表面的Ce3 + 浓度分别与苯甲醇氧化反应的TOF值之间存在较好的线性关系,Pd与CeO2形成的界面位点(Pd–O–Ce)是这类醇氧化催化剂的主要催化位点。本研究有助于认识金属和氧化物载体界面位点的催化作用,从而开发更好的醇氧化催化剂。

     

    Abstract: The oxidation of alcohols is a significant chemical reaction, and the efficient oxidation of alcohols over heterogeneous catalysts using oxygen as oxidant has attracted much attention in recent years. Among them, Pd/CeO2 exhibits excellent alcohol oxidation performance. However, the structure-activity relationship between the catalyst’s structure and its catalytic performance for alcohol oxidation is still not clearly understood. This study involved the preparation of CeO2 nanosheets with different concentrations of surface oxygen vacancies (Ov) and their subsequent loading with Pd to explore their catalytic performance for alcohol oxidation. The findings obtained through XPS, Raman, and XAS indicated a positive correlation between the surface Ov concentration of CeO2 as well as the ratio of Pd2+ fraction. The alcohol oxidation results and structure-performance relationship studies showed that there was a good linear relationship between the Pd2+ ratio as well as the surface Ce3+ concentration and the TOF of benzyl alcohol oxidation reaction, respectively. And the interfacial site (Pd–O–Ce) formed by Pd and CeO2 was the main catalytic site for this type of alcohol oxidation catalysts. This study contributes to the understanding of the catalytic role of interfacial sites in metal and oxide support for the development of better alcohol oxidation catalysts.

     

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