Public Research Seminar by Sustainable Energy and Environment Thrust, HKUST(GZ) - Electron microscopy imaging of electron bean-sensitive crystalline materials & Constructing New Porous Frameworks by Designing Connection Bonds and Building Blocks
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Electron microscopy imaging of electron bean-sensitive crystalline materials
This presentation will focus on our recent works pertaining to the high-resolution imaging of electron beam-sensitive materials using ultralow electron doses. The following technological advances will be discussed. First, the development of a suite of methods to address the challenges peculiar to low-dose TEM imaging, including rapid search for crystal zone axes, precise alignment of the image stack, and accurate determination of the defocus value, enables efficient imaging of electron beam-sensitive crystalline materials in the high-resolution TEM (HRTEM) mode. Second, integrated differential phase contrast STEM (iDPC-STEM) has proven to be an effective method for acquiring directly interpretable atomic-resolution images under low-dose conditions. Third, cryogenic focused ion beam (cryo-FIB) has demonstrated a unique power to prepare (S)TEM specimens for highly sensitive materials. Finally, I will share my views on the great potential of four-dimensional STEM (4D-STEM) in imaging highly electron beam-sensitive materials and provide preliminary results to demonstrate its feasibility.
Constructing New Porous Frameworks by Designing Connection Bonds and Building Blocks
By rationally designing connection bonds and building blocks, three kind of novel porous frameworks were successfully constructed:
(i) Crystalline metal-carbon framework (MC-MOF) materials were synthesized using M-C bonds as linking modules. Their structures were systematically characterized by PXRD, EXAFS, and advanced TEM techniques, providing detailed structural insights.
(ii) Two crystalline phases of hydrogen-bonded porous organic cages (HPOC-α and HPOC-β) were developed for uranium extraction from seawater. Structural analyses revealed that accessible active sites are critical for uranyl ion adsorption. U(VI) adsorption experiments demonstrated that HPOC-α exhibits an exceptional uranium capacity of 1728 mg g⁻¹, maintaining stability even after seven adsorption-desorption cycles.
(iii) The extended tetrahedral monomer tetrakis(4’-bromo-[1,1’-biphenyl]-4-yl)methane was employed to construct a mesoporous dia-topology framework (PAF-333). Five Ni(0) ligands with different molecular sizes were used to study the template effect on mesoporous formation. Notably, larger ligands induced steric hindrance that effectively prevented framework interpenetration. PAF-333 showed outstanding thermal stability up to 450 °C, along with promising gas storage capabilities: a hydrogen delivery capacity of 10.2 wt% at 77 K and 100 bar, and a methane adsorption capacity of 0.537 g g⁻¹ at 298 K and 98 bar, positioning it as a versatile material for gas storage applications.
Dr. Yu Han obtained his PhD from Jilin University in 2003 and served as a research scientist at A-Star in Singapore from 2003 to 2008. Between 2009 and 2023, he worked at King Abdullah University of Science and Technology in Saudi Arabia as a professor in the Department of Chemistry and Chemical Engineering. In September 2023, he joined South China University of Technology as the Director of the Center for Electron Microscopy.
Dr. Han's research primarily focuses on the synthesis and application of porous materials (catalysis, separation, water treatment) and high-resolution electron microscopy imaging of electron beam-sensitive materials. He is a co-inventor of ultralow-dose electron microscopy imaging technology. He has published over 400 academic papers, including in prestigious journals such as Nature, Science, Nature Nanotechnology, Nature Chemistry, and Nature Materials, with a total citation count exceeding 50,000 and an H-index of 120.
Dr. Han was recognized as one of the top 100 young inventors by MIT's Technology Review magazine in 2004, received the Young Scientist Award in Singapore in 2006, the Thomson Reuters Research Fronts Award in 2008, was named a Chang Jiang Scholar Lecture Professor by the Ministry of Education of China in 2016, received the Humboldt Research Award in 2021, and was a Clarivate Analytics Highly Cited Researcher for five consecutive years from 2019 to 2024.
Jiangtao Jia is from Northeast Normal University. He obtained his Ph.D. from Jilin University in 2014 under the supervision of Guangshan Zhu. He did postdoctoral research and served as a research scientist at the Institute for Basic Science (IBS, South Korea, with Kimoon Kim, 2014-2015) and King Abdullah University of Science and Technology (KAUST, Saudi Arabia, with Mohamed Eddaoudi, 2015-2022). He has published over 50 articles in journals including Nature，Science, Chem, J. Am. Chem. Soc., Angew. Chem. Int. Ed. His current research focuses on rational design and synthesis of porous materials.
For inquiries, please contact Miss Summer XIE (+86-20-8833 2977, summerxmxie@hkust-gz.edu.cn)