Crystal Structural Effect of AuCu Alloy Nanoparticles on Catalytic CO Oxidation.
Crystal Structural Effect of AuCu Alloy Nanoparticles on Catalytic CO Oxidation.
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DOI：
10.1021/jacs.7b01784
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发表时间：
2017-06
影响因子：
15
通讯作者：
Wangcheng Zhan;Jinglin Wang;Haifeng Wang;Jinshui Zhang;Xiaofei Liu;Pengfei Zhang;M. Chi;Yanglong Gu
中科院分区：
文献类型：
--
作者：
Wangcheng Zhan;Jinglin Wang;Haifeng Wang;Jinshui Zhang;Xiaofei Liu;Pengfei Zhang;M. Chi;Yanglong Gu
控制合金纳米粒子的物理和化学性质是优化纳米粒子催化性能的重要途径。与其他调节旋钮（如大小、形状和成分）不同，晶体结构受到的关注有限，并且没有很好地理解其在催化中的作用。这一缺陷主要是由于纳米粒子的晶体结构的合成和微调的困难。在这里，以具有面心立方（fcc）和面心四面体（fct）结构的AuCu合金纳米颗粒为例，我们证明了取决于晶体结构的相分离和催化性能的显著差异。在空气中的热处理过程中，与fct-AuCu合金纳米颗粒相比，fcc-AuCu合金纳米颗粒中的Cu组分更容易偏析到合金表面上。结果，在250 °C下在空气中退火1小时后，fcc-和fct-AuCu合金NP分别相转移成Au/CuO和AuCu/CuO核/壳结构。更重要的是，这种异质结构的变化引入了一个显着的差异CO吸附在两种催化剂上，从而大大提高了催化活性的AuCu/CuO NP催化剂CO氧化。同样的概念可以扩展到其他合金纳米粒子，使其有可能微调纳米粒子催化许多不同的化学反应。
Controlling the physical and chemical properties of alloy nanoparticles (NPs) is an important approach to optimize NP catalysis. Unlike other tuning knobs, such as size, shape, and composition, crystal structure has received limited attention and not been well understood for its role in catalysis. This deficiency is mainly due to the difficulty in synthesis and fine-tuning of the NPs' crystal structure. Here, Exemplifying by AuCu alloy NPs with face centered cubic (fcc) and face centered tetragonal (fct) structure, we demonstrate a remarkable difference in phase segregation and catalytic performance depending on the crystal structure. During the thermal treatment in air, the Cu component in fcc-AuCu alloy NPs segregates more easily onto the alloy surface as compared to that in fct-AuCu alloy NPs. As a result, after annealing at 250 °C in air for 1 h, the fcc- and fct-AuCu alloy NPs are phase transferred into Au/CuO and AuCu/CuO core/shell structures, respectively. More importantly, this variation in heterostructures introduces a significant difference in CO adsorption on two catalysts, leading to a largely enhanced catalytic activity of AuCu/CuO NP catalyst for CO oxidation. The same concept can be extended to other alloy NPs, making it possible to fine-tune NP catalysis for many different chemical reactions.