Wang Xiao, Liu Dapeng, Li Junqi, Zhen Jiangman, Wang Fan, Zhang Hongjie
State Key Laboratory of Rare Earth Resource Utilization , Changchun Institute of Applied Chemistry , Chinese Academy of Sciences , Changchun 130022 , Jilin , China . Email:
Graduate School of The Chinese Academy of Sciences , Beijing 100039 , China.
Chem Sci. 2015 May 1;6(5):2877-2884. doi: 10.1039/c4sc03854a. Epub 2015 Feb 27.
In this paper, we have successfully demonstrated the clean synthesis of high-quality Pd@CeO core@shell nanospheres with tunable Pd core sizes in water, and furthermore loaded the as-obtained Pd@CeO products on commercial γ-AlO electrostatic interaction. KBr here plays two key roles in inducing the growth and self-assembly of Pd@CeO core@shell nanospheres. First, Br ions can retard the reduction of Pd ions the formation of the more stable complex of [PdBr] so as to tune the size of Pd cores. Second, it greatly decreases the colloidal stability, and hence the surface polarity-weakened Pd and CeO NPs have to spontaneously self-assemble into more stable and ordered structures. Among different-sized Pd samples, the as-obtained 8 nm-Pd@CeO/AlO one exhibits the best performance in catalytic CO oxidation, which can catalyze 100% CO conversion into CO at 95 °C, which is much lower than the previously reported CeO-encapsulated Pd samples.
在本文中，我们成功地证明了在水中可通过调节钯核尺寸来实现高质量的钯@二氧化铈核壳纳米球的清洁合成，并且进一步通过静电相互作用将所获得的钯@二氧化铈产物负载在商用γ-氧化铝上。此处的溴化钾在诱导钯@二氧化铈核壳纳米球的生长和自组装过程中起到两个关键作用。首先，溴离子可以延缓钯离子的还原，形成更稳定的[PdBr]络合物，从而调节钯核的尺寸。其次，它极大地降低了胶体稳定性，因此表面极性减弱的钯和二氧化铈纳米颗粒不得不自发地自组装成更稳定、更有序的结构。在不同尺寸的钯样品中，所获得的8纳米钯@二氧化铈/氧化铝样品在催化一氧化碳氧化方面表现出最佳性能，它能在95℃下催化100%的一氧化碳转化为二氧化碳，这比先前报道的二氧化铈包裹的钯样品所需温度低得多。
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