后台 - 高 传博
Tingting's recent work on encapsulation of ultrasmall Au nanoparticles for high-temperature catalysis has been published in ACS Nano. Congratulations!
Title: Unconventional Route to Encapsulated Ultrasmall Gold Nanoparticles for High-Temperature Catalysis
Authors: Zhang, T,; Zhao, H.; He, S.;Liu, K,; Liu, H.;* Yin, Y.;* Gao, C.*
Link to Publisher: http://pubs.acs.org/doi/abs/10.1021/nn502349k.
Highlight by XJTU: http://news.xjtu.edu.cn/info/1004/43140.htm
Abstract: Ultra-small gold nanoparticles (us-AuNPs, < 3 nm) have been recently recognized as surprisingly active and extraordinarily effective green catalysts. Their stability against sintering during reactions however remains a serious issue for practical applications. Encapsulating such small nanoparticles in a layer of porous silica can dramatically enhance the stability, but it has been extremely difficult to achieve using conventional sol-gel coating methods due to the weak metal/oxide affinity. In this work, we address this challenge by developing an effective protocol for the synthesis of us-AuNP@SiO2 single-core/shell nanospheres. More specifically, we take an alternative route by starting with ultra-small gold hydroxide nanoparticles, which have excellent affinity to silica, then carrying out controllable silica coating in reverse micelles, and finally converting gold hydroxide particles into well-protected us-AuNPs. With a single-core/shell configuration that prevents sintering of nearby us-AuNPs and amino group modification of the Au/SiO2 interface that provides additional coordinating interactions, the resulting us-AuNP@SiO2 nanospheres are highly stable at high temperatures, and show high activity in catalytic CO oxidation reactions. A dramatic and continuous increase in the catalytic activity has been observed when the size of the us-AuNPs decreases from 2.3 nm to 1.5 nm, which reflects the intrinsic size effect of the Au nanoparticles on an inert support. The synthesis scheme described in this work is believed to be extendable to many other ultra-small metal@oxide nanostructures for much broader catalytic applications.