CAS key laboratory of Low-Carbon Conversion Science and Engineering, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China.
Nanoscale. 2016 Jun 7;8(21):10896-901. doi: 10.1039/c6nr02477g. Epub 2016 May 13.
The control of the curved structure of bimetallic nanocrystals is a challenge, due to the rate differential for atom deposition and surface diffusion of alien atomic species on specific crystallographic planes of seeds. Herein, we report how to tune the degree of concavity of bimetallic PtxCoy concave nanoparticles using carboxylic acids as surfactants with an oleylamine system, leading to the specific crystallographic planes being exposed. The terminal carboxylic acids with a bridge ring or a benzene ring serving as structure regulators could direct the formation of curved faces with exposed high-index facets, and long-chain saturated fatty acids favored the production of curved faces with exposed low-index facets, while long-chain olefin acids alone benefited the formation of a flat surface with exposed low-index planes. Furthermore, these PtxCoy particles with curved faces displayed superior catalytic behaviour to cinnamaldehyde hydrogenation when compared with PtxCoy with flat faces. PtxCoy nanoparticles with curved faces exhibited over 6-fold increase in catalytic activity compared to PtxNiy nanoparticles with curved faces, and near 40-fold activity increase was observed in comparison with PtxFey nanoparticles with curved faces.
控制双金属纳米晶体的弯曲结构是一个挑战，这是由于在种子的特定晶面，异类原子的原子沉积和表面扩散速率存在差异。在此，我们报告了如何使用羧酸作为表面活性剂，在油胺体系中调节 Pt x Co y 凹型纳米颗粒的凹陷程度，从而暴露特定的晶面。具有桥环或苯环作为结构调节剂的末端羧酸可以引导形成具有暴露的高指数晶面的弯曲面，而长链饱和脂肪酸有利于形成具有暴露的低指数晶面的弯曲面，而长链烯烃酸则有利于形成具有暴露的低指数晶面的平坦表面。此外，与具有平坦表面的 Pt x Co y 相比，具有弯曲表面的 Pt x Co y 颗粒在肉桂醛加氢反应中表现出更好的催化性能。与具有弯曲表面的 Pt x Ni y 纳米颗粒相比，具有弯曲表面的 Pt x Co y 纳米颗粒的催化活性增加了 6 倍以上，与具有弯曲表面的 Pt x Fe y 纳米颗粒相比，活性增加了近 40 倍。
