The Tunable and Highly Selective Reduction Products on Ag@Cu Bimetallic Catalysts Toward CO2 Electrochemical Reduction Reaction
The Tunable and Highly Selective Reduction Products on Ag@Cu Bimetallic Catalysts Toward CO2 Electrochemical Reduction Reaction
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DOI：
10.1021/acs.jpcc.7b01586
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发表时间：
2017-06-01
影响因子：
3.7
通讯作者：
Wang, Hailiang
中科院分区：
文献类型：
--
作者：
Chang, Zhiyuan;Huo, Shengjuan;Wang, Hailiang
双金属电催化剂可以通过调整其结构、形态和组成来提高其活性和选择性。然而，目前还没有一个系统的模型来理解CO对电化学还原反应的结构效应关系，特别是引入第二金属生长到外层的产品调谐过程。在此，我们报告了一个结构控制模型，该模型是通过多元醇方法制备的Ag@Cu双金属纳米颗粒的生长过程，即在聚乙烯吡咯烷酮存在的情况下，在乙二醇（还原剂）中还原Ag+和Cu2+（过量）的混合物。结构表征表明，通过控制加热时间（0-25 min），一系列Ag@Cu NPs从Ag核心（Cu修饰Ag）调整到Cu外壳。此外，还可以实现高选择性的催化剂，将一氧化碳还原产物调谐为碳氢化合物。不同于Ag和Cu之间的“稀释”效应，Cu的引入检测到一氧化碳生成的火山曲线，峰值点为Ag@Cu-7电催化剂（加热时间为7 min）。同样有趣的是，当Cu包层不断增长时，碳氢化合物不是简单的比例添加，并在Ag@Cu-20（加热时间为20 min）优化。几何效应主要解释了CO产物的协同作用，并控制了对烃类的表面活性。本研究为调整中间结合的能量学以实现核壳结构催化剂更高的选择性和活性提供了一个良好的起点。
Bimetallic electrocatalysts can improve the activity and selectivity over their monometallic counterparts by tuning the structure, morphology, and composition. However, there scarcely was a systematic model to understand the structural effect relationship on CO, electrochemical reduction reaction, especially for a product tuning process by introduction of a second metal to grow into outer layers. Herein, we report a structure-controlled model of the growth process of Ag@Cu bimetallic nanoparticles that are fabricated by a polyol method, that is, reducing mixtures of Ag+ and Cu2+ (excess amount) in ethylene glycol (reducing agent) in the presence of polyvinylpyrrolidone. Structural characterizations reveal that a series of Ag@Cu NPs are tuned from the Ag core, Cu modified Ag, to the Cu outer shell by controlling the heating time (0-25 min). Moreover, highly selective catalysts with the tuning reduction products from carbon monoxide to hydrocarbons can be realized. Different from the "dilution" effects between Ag and Cu, the volcanic curve for carbon monoxide production is detected for the introduction of Cu and the peak point is the Ag@Cu-7 electrocatalyst (heating time is 7 min). Similarly, interestingly, when the Cu cladding layer continuously grows, the hydrocarbons are not a simple proportional addition and optimized at Ag@Cu-20 (heating time is 20 min). The geometric effects dominantly account for the synergistic effect of CO product and control the surface activity to hydrocarbons. This study serves as a good starting point to tune the energetics of the intermediate binding to achieve even higher selectivity and activity for core shell structured catalysts.