Low-Dimensional Nanostructures for Effective Energy Conversation and Storage
Effective energy conversion and storage play a key role in tackling the energy trilemma of security, affordability and sustainability. Carbon / graphene -based materials offer great scope for cost-efficient 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 architecting, 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 further development of highly cost-effective energy storage technologies on a large scale.
郭正晓教授1983年获东北大学学士学位;1984年和1988年分别获得曼彻斯特大学硕士和博士学位，之后分别在斯特拉斯克莱德大学(1988-90年)和牛津大学(1990-95年)担任研究员。他曾在伦敦大学玛丽皇后学院材料系担任讲师(1995-98)、读者(1998-99)和教授(2000-07)，2007年至2018年，他在伦敦大学学院(UCL)担任材料化学教授。最近郭正晓教授加入了香港大学，担任理工科的联合教授和香港大学浙江研究创新学院的执行董事。郭教授的课题组主要进行高功能原子簇、纳米结构和材料的合成设计与理论研究。他在能源、环境、航空航天和生物医学领域发表了300多篇高质量的期刊论文和300多篇会议报告，包括Energy and Environmental Sciences (x6), Advanced (Energy/Functional) Materials (x7), Nano Letters (x2), Angewandte Chemie Inter Ed (x1), Chemical Science (x1), Chemistry of Materials (x1), and invited reviews in Progress in Materials Science (x2)等多篇。2000年被英国材料学会、皇家化学会与化学工业学会联合授予贝尔比奖章与奖金。