Frontier Institute of Science and Technology and State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China.
Center for Advancing Materials Performance from the Nanoscale, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
Nat Commun. 2017 Nov 2;8(1):1261. doi: 10.1038/s41467-017-01258-0.
The Kirkendall effect has been recently used to produce hollow nanostructures by taking advantage of the different diffusion rates of species involved in the chemical transformations of nanoscale objects. Here we demonstrate a nanoscale Kirkendall cavitation process that can transform solid palladium nanocrystals into hollow palladium nanocrystals through insertion and extraction of phosphorus. The key to success in producing monometallic hollow nanocrystals is the effective extraction of phosphorus through an oxidation reaction, which promotes the outward diffusion of phosphorus from the compound nanocrystals of palladium phosphide and consequently the inward diffusion of vacancies and their coalescence into larger voids. We further demonstrate that this Kirkendall cavitation process can be repeated a number of times to gradually inflate the hollow metal nanocrystals, producing nanoshells of increased diameters and decreased thicknesses. The resulting thin palladium nanoshells exhibit enhanced catalytic activity and high durability toward formic acid oxidation.
近年来，人们利用不同物种在纳米尺度物体化学转化中扩散速率的差异，通过柯肯达尔效应来制备中空纳米结构。在此，我们通过磷的插入和提取，展示了一种纳米尺度的柯肯达尔空化过程，可将钯纳米晶转化为钯空心纳米晶。成功制备单金属中空纳米晶的关键在于通过氧化反应有效提取磷，这促进了磷化钯复合纳米晶中磷向外扩散，同时空位向内扩散并聚集成更大的空洞。我们进一步证明，这种柯肯达尔空化过程可以重复多次，逐渐膨胀中空金属纳米晶，生成直径更大、厚度更小的纳米壳。所得到的钯纳米壳具有增强的甲酸氧化催化活性和高耐久性。
