Modifying the Surface of gamma-Al2O3 with Y2Sn2O7 Pyrochlore: Monolayer Dispersion Behaviour of Composite Oxides
Modifying the Surface of gamma-Al2O3 with Y2Sn2O7 Pyrochlore: Monolayer Dispersion Behaviour of Composite Oxides
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Y2Sn2O7 烧绿石修饰γAl2O3 表面：复合氧化物的单层分散行为
DOI：
10.1002/cphc.201700029
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发表时间：
2017
期刊：
影响因子：
2.9
通讯作者：
Wang Xiang
中科院分区：
文献类型：
--
作者：
Xu Xianglan;Liu Fang;Tian Jinshu;Peng Honggen;Liu Wenming;Fang Xiuzhong;Zhang Ning;Wang Xiang
为了研究复合氧化物在载体上的分散行为，为获得更好的Pd催化CO氧化载体，采用沉积-沉淀法制备了一系列不同负载量的Y2Sn2O7/Al2O3复合氧化物。X射线衍射和X射线光电子能谱外推方法表明，与单一金属氧化物类似，复合氧化物也可以自发分散在载体表面，形成具有一定容量的单分子膜。Y2Sn2O7在γ-Al_2O_3表面的单层分散容量/阈值为0.109 /100 m~2γ-Al_2O_3，相当于7.2wt %Y2Sn2O_7的负载量。这是第一个展示复合氧化物在载体上单层分散的工作。Y2Sn2O7与γ-Al_2O_3结合后，可在催化剂表面引入活性氧物种。与单组分Y2Sn2O7载体相比，Pd与载体之间的相互作用增强，Pd的分散性提高，Pd与复合载体之间产生协同效应，有利于催化剂的活性。通过在γ-Al_2O_3表面添加不同量的焦绿石Y2Sn2O_7，提高了1 %Pd/Y2Sn2O_7/Al_2O_3催化剂的CO氧化活性。这些发现为设计和制备贵金属含量较低的高效负载型贵金属催化剂提供了新的思路。
To investigate the dispersion behaviour of composite oxides on supports, and to obtain better supports for Pd for CO oxidation, a series of Y2Sn2O7/Al2O3composite oxides with different Y2Sn2O7loadings were prepared by a deposition–precipitation method. XRD and X‐ray photoelectron spectroscopic extrapolation methods revealed that, similar to single‐component metal oxides, composite oxides can also disperse spontaneously on support surfaces to form a monolayer with a certain capacity. The monolayer dispersion capacity/threshold for Y2Sn2O7on the surface of γ‐Al2O3is 0.109 mmol per 100 m2γ‐Al2O3, corresponding to 7.2 wt % Y2Sn2O7loading. This is the first work to demonstrate monolayer dispersion of a composite oxide on a support. After combining Y2Sn2O7with γ‐Al2O3, active oxygen species can be introduced onto the catalyst surfaces. Thus, the interaction between Pd and the support is strengthened, the dispersion of Pd is improved in comparison with the single‐component Y2Sn2O7support, and a synergistic effect is induced between Pd and the composite support, which is beneficial to catalyst activity. By tuning the γ‐Al2O3surface with different amounts of pyrochlore Y2Sn2O7, CO oxidation activity on 1 % Pd/Y2Sn2O7/Al2O3was improved. These findings may provide new insights into the design and preparation of effective supported noble metal catalysts with lower contents of noble metals.