报告题目：Engineering Low Dimensional Structures for Effective Energy Conversion and Storage

　　报告人：Professor Zheng-Xiao Guo (The University of Hong Kong)

　　时间：5月24日（周五）9:30-11:00

　　地点：李薰楼468房间

　　Engineering Low Dimensional Structures for Effective Energy Conversion and Storage

　　Professor Zheng-Xiao Guo,

　　Departments of Chemistry and Mech Engineering, The University of Hong Kong;

　　HKU Zhejiang Institute of Research and Innovation, Hangzhou, China;

　　University College London, 20 Gordon Street, London WC1H 0AJ,UK

　　(zxguo@hku.hk; z.x.guo@ucl.ac.uk)

Low-dimensional structures offer great scope for chemical / electrochemical /photochemical energy storage and catalysis, while the exceptional physical and mechanical properties are also utilised. Such functionalities can be effectively tuned by means of atomic doping, defect control, inter-layer spacing, porosity architecturing, and hybridisation with other nanostructures. The focus here is to demonstrate how those approaches can be effectively engineered to the development of storage materials for hydrogen, methane and CO₂, and of electrochemical catalysts for oxygen reduction and/or evolution reactions (ORR or OER), which underpins the costs and stability of rechargeable metal–air batteries and regenerative fuel cells – the energy conversion / storage technologies for portable devices, electric vehicles and the smart grid. Currently, the commercial noble metal catalysts, such as Pt/C and Ir/C, only exhibit mono-functional activity for either ORR or OER. Non-noble metal or metal-free materials are increasingly considered as cost-effective alternatives, but their catalytic activities, especially OER performance, are yet to match their metallic counterparts. Our systematic development firstly demonstrates the enrichment of N-doping and graphene / graphitic carbon-nitride intercalation are effectively for enabling rapid four-electron transfer process in ORR, and then switching of ORR and OER by single heat-treatment of a metal-organic-framework. Finally by closely coupling theory and experiment, we show the most effective catalytic sites in phosphorus-nitrogen co-doped graphene frameworks (PNGF), and then engineered the synthetic formulations to enrich such sites. The developed electrocatalysts show highly efficient bifunctionality for both ORR and OER. The ORR/OER potential gap is reduced successively from the initial 1.252 mV, to 1.037 mV with P,N co-doping, then to 795 mV after PNGF optimisation, and finally to 705 mV after purposeful enrichment of the active P–N sites. This design strategy, synthesis approach and the efficient catalysts offer great opportunities for the development of highly cost-effective energy storage technologies on a large scale.

Curriculum Vitae

ZXG has recently joint the University of Kong Hong as a joint-faculty Professor of Chemistry and Mechanical Engineering and the Executive Director of HKU Zhejiang Institute of Research and Innovation, and is an Honorary Professor of University College London (UCL) (2018-) and a Fellow of Royal Society of Chemistry. He was a Professor of Chemistry and a Pro-Provost at UCL, and a Lecturer / Professor at Queen Mary, University of London, a research fellow at the University of Oxford and of Strathclyde, respectively, with a PhD from the Univ. of Manchester in 1988. Prof. Guo’s group focuses on integrated theoretical and experimental approaches for the design and development of highly functional atomic clusters, nanostructures and materials, as well as their synthesis and manufacturing processes. He has contributed over 300 high-quality journal publications and over 300 conference papers / presentations (over 100 keynote/invited) for energy, environmental and biomedical applications. He was awarded the Sir Beilby Medal (as the 1^st recipient of Chinese heritage), jointly by the Society of Chemical Industry, the Royal Society of Chemistry, and the Institute of the Minerals, Metals and Materials. Quality outputs include Energy & Environmental Sciences (x6), Advanced Materials series (x8), Phys. Rev. Lett. (x1), Nano Letters (x2), Angewandte Chemie Inter Ed (x1) and invited reviews in Progress in Materials Science (x2). He has led various consortium projects (over ￡70m). He was the “Focal-Point” for UK-China collaborations in Nano- & Materials Science, an overseas expert advisor to the Bureau of Overseas Chinese of the State Council, and the Chinese Academy of Sciences; the UK Lead, Theme Leader and Executive Management Committee member of the EU Consortium on “Adv. Materials & Processes for Energy Applications” / EU Energy Research Alliance; a Member of the RSC Publishing Board.