Thermally stable ultra-small Pd nanoparticles encapsulated by silica: elucidating the factors determining the inherent activity of noble metal catalysts
Thermally stable ultra-small Pd nanoparticles encapsulated by silica: elucidating the factors determining the inherent activity of noble metal catalysts
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二氧化硅封装的热稳定超小钯纳米粒子：阐明决定贵金属催化剂固有活性的因素
DOI：
10.1039/c6cy00201c
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发表时间：
2016
影响因子：
5
通讯作者：
Wang Xiang
中科院分区：
文献类型：
--
作者：
Ying Jiawei;Peng Honggen;Xu Xianglan;Wang Ruonan;Yu Fan;Sun Qi;Liu Wenming;Gao Zhixian;Wang Xiang
采用改进的一步反胶束法，一锅法制备了具有热稳定性的1.1 nm超小Pd纳米粒子Pd@SiO2-RM。HRTEM结果表明，超小Pd纳米粒子嵌入到30 nm左右的SiO2纳米球中，形成多核壳结构。因此，在升高的温度下，可以有效地阻止超小Pd纳米颗粒核的迁移和团聚。与浸渍法制备的Pd/SiO2-IMP、Stober法制备的Pd@SiO2-ST和常规微乳液法制备的Pd@SiO2-ME相比，Pd@SiO2-RM具有更高的金属比表面积。结果表明，该催化剂对CO氧化具有显著的活性和上级热稳定性。它的结论是，Pd晶粒尺寸和金属表面积的活性的决定因素，证明了微分速率和Pd尺寸/金属表面积之间的严格线性关系。
With an improved one-step reverse micelle method, Pd@SiO2-RM with thermally stable, 1.1 nm ultra-small Pd nanoparticles were prepared in one-pot. HRTEM results reveal that the ultra-small Pd nanoparticles are embedded in the bulk of the silica nanospheres around 30 nm to form a multi-core shell structure. Therefore, the migration and agglomeration of the ultra-small Pd nanoparticle cores can be impeded effectively at elevated temperatures. Compared with Pd/SiO2-IMP prepared by impregnation, core–shell Pd@SiO2-ST and Pd@SiO2-ME catalysts prepared by Stober and regular micro-emulsion processes, Pd@SiO2-RM possesses a much higher metal surface area. As a consequence, this catalyst shows remarkable activity and superior thermal stability for CO oxidation. It is concluded that the Pd grain size and metal surface area are the determining factors for the activity, as evidenced by the strict linear relationship between the differential rates and the Pd sizes/metal surface areas.