报告题目: Atomic-scale characterisation of catalyst materials by atom probe tomography
报告时间：2018年10月30日上午10点30分
报告地点：浙江大学玉泉校区铸工楼201C
邀请人：吴琛副教授
报告摘要:
Bimetallic heterogeneous catalysts have proven remarkably successful in catalysing a wide range of important processes, in fuel-cells, exhaust emission control and in water electrolysers. However, the effects of the operating environment on the surface composition, structure and stability of the noble metal catalysts are poorly understood at the atomic-scale. This knowledge will be required to produce the improved catalysts needed for future energy- and materials-efficient technologies.
Atom probe tomography (APT) offers a unique method for studying these materials, offering atomic-scale chemical identities of the catalyst surfaces and chemisorbed species. Here, APT was employed to investigate a rich variety of behaviour in platinum group metals and alloys exposed to high temperature oxidation or electro-oxidation. The results reveal pronounced surface segregation behaviour, strongly dependent on the treatment conditions, crystallographic plane and alloy composition. Furthermore, while subsequent reduction treatments remove formed oxides, the marked changes to the metallic surface compositions remain. Such results suggest using sequential oxidation and reduction treatments as an alternative synthesis method for designing and preparing nano catalysts with controlled surface compositions.
Another aspect focuses on the investigation of the use of APT for characterising catalyst nanoparticles either in colloidal dispersions or on the carbon supports. It is very challenging to fully characterise these complex 3D architectures by conventional electron microscope technique. In this work, the use of APT for the analysis and characterisation of catalyst nanoparticles will be demonstrate. Alongside a description of the preparations, I will also present a range of results from these catalysts materials, highlighting the correction between catalytic efficiency and the atomic-scale chemical/structural information uniquely provided by APT.
报告人简介:
Tong Li is anassistant professor for ‘characterisation of high-performance materials at the atomic scale’ in the Institute for Materials at Ruhr University Bochum in Germany. She obtained her PhD in Materials Science at the University of Oxford in 2011. She was a post-doctoral research associate in the Australian Centre for Microscopy and Microanalysis at the University of Sydney and Alexander von Humboldt research fellow at Max-Planck Institute for Ion Research in Germany. She is currently establishing a junior research group in the centre for interface-dominated high-performance materials (ZGH) at Ruhr University Bochum. Her research interests centre on the application of advanced characterisation techniques for the development of new functional and structural materials. She is currently investigating a wide range of materials such as advanced titanium alloys for aerospace, and catalyst nanoparticles for water splitting.
