简介: In this contribution, we will present several examples for the application of high-resolution electron microscopy in characterizing nano-structured materials and heterogeneous catalysts: (i) electron crystallography is applied to resolve the first as well as the only tri-continuous mesoporous structure IBN-9. The results shows that IBN-9 consists of three identical 3-D mesoporous channels interwoven with each other and separated by a single continuous silica wall that follows a branched hexagonal minimal surface (Figure 1) ^[1]; (ii) Surface reconstruction on a complex metal oxide catalyst is identified by combining focused ion beam (FIB) for specimen preparation and Cs-corrected STEM for high-resolution imaging ^[2]; and (iii) we synthesized a novel Au-Pd bimetallic nanostructure (HIF-AuNR@AuPd) through site-specific epitaxial growth of Au-Pd alloy horns as catalytic sites at the ends of Au nanorods. Using electron microscopy and tomography, we successfully reconstructed the complex three-dimensional morphology of HIF-AuNR@AuPd. With an electron beam probe, we visualized the distribution of surface plasmon over the HIF-AuNR@AuPd nanorods. This unique material couples high catalytic activity with a strong SERS effect at the rod ends, serving as an excellent bifunctional platform for in-situ monitoring of surface catalytic reactions ^[3].

 

[1] Yu Han, Daliang Zhang, Leng Leng Chng, Junliang Sun, Lan Zhao, Xiaodong Zou and Jackie Y. Ying,  Nature Chemistry 1 (2009), 123-127

[2] Yihan Zhu, Qingxiao Wang, Lan Zhao, Yu Han*, Angew. Chem. Int. Ed. 51 (2012) 4176-4180

[3] Jianfeng Huang, Yihan Zhu, Ming Lin, Qingxiao Wang, Lan Zhao, Yang Yang, Kexin Yao, and Yu Han*, J. Am. Chem. Soc., (2013) DOI: 10.1021/ja4004602

 

报告人简介：

Dr Han is a material scientist and his research is focused on nanoporous materials. His special ability to well control the structure and morphology of these materials promoted his great success in developing novel applications for them. He synthesized the first tri-continuous mesoporous material that possesses three identical interpenetrating channels. This work was published in Nature Chemistry and highlighted by Nature in 2009. He has developed new synthesis routes for mesoporous materials which significantly improve their stability and therefore their usability as catalysts in petroleum chemistry. He has also developed a generalized fluorocarbon surfactant-mediated method for synthesizing mesoporous nanoparticles, which enables the unprecedented, simultaneous control of particle size and porous structure. Recently, he synthesized helical mesoporous silica with chiral channels from achiral system and achieved the systematical control of the helical pitch. Dr. Han is also a specialist in transmission electron microscopy (TEM). Using TEM, he has characterized many nanoporous or nanostructured materials.

Dr Han has published 74 articles in international refereed journals, including 1 in Nature, 1 in Nature Chemistry, 1 in Nature Materials, 5 in Angew. Chem. Int. Ed., 1 in Adv. Mater, 6 in J. Am. Chem. Soc., 1 in Chem. Comm., 14 in Chem. Mater., 7 in J. Phys. Chem., 3 in Chem. Eur. J. and these papers have been cited over 3000 times with h-index = 28.