NOTTINGHAM TRENT UNIVERSITY - INVESTING IN EXCELLENCE VICE-CHANCELLOR’S PHD SCHOLARSHIP SCHEME 2014 & SCHOOL PHD SCHOLARSHIPS (entry in 2015/16) SCHOOL: School of Science and Technology PROJECT TITLE: Computational Pathways to Higher Efficiency Solid Oxide Fuel Cells. PROJECT LEAD: Christopher Castleton Overview: In this PhD project you will use advanced atomic scale quantum mechanical computer modelling (density functional theory – DFT) to study key microscopic processes at metal/metal oxide interfaces in the context of Solid Oxide Fuel Cells (SOFCs). The results will also be applicable to other developing green technologies, including green catalysis and oxide based gas sensors. You will be trained in fore-front computational methods for the theoretical study, simulation and prediction of the properties of materials. (The project will not involve significant amounts of programming as the codes already exist.) These methods are equally applicable to a wide variety of other important questions in both basic materials physics and in industrial and environmental applications, and have been applied in areas ranging from molecular biology and geology to semiconductor engineering and nano-technology. As a result, this PhD project would prepare you for a wide range of possible careers within both academic and industrial R&D sectors. Scientific Overview: The properties of defects, surfaces and interfaces between materials, and their theoretical description/prediction remains one of the big challenges in condensed matter physics, and DFT provides one of the most powerful tools for studying them. There are important questions to be answered in the basic science of these systems, and the results obtained can have have important implications for a wide range of in industrial and environmental applications. In particular, metal/metal oxide interfaces are vital to several current and developing green technologies, including green catalysis, oxide based gas sensors and solid oxide fuel cells (SOFCs). For all of these there are both commercial and environmental needs to improve performance and lower costs, and the search for new innovative solutions involves detailed study of atomic scale processes and mechanisms. This project will focus on Cu/CeO 2 interfaces, which have several applications. We will address specific current issues with two of the most important. SOFCs convert the chemical energy in a fuel (H 2 or a hydrocarbon) directly into electricity with very high efficiencies, as compared to burning it in an internal combustion engine. This improved efficiency means a far smaller carbon footprint, but several materials issues currently limit the commercial impact of SOFCs. One is “coking” of the anodes (carbon build-up blocking chemically active surface sites in the part of the SOFC where the actual fuel to electricity conversion occurs), which are commonly made of Ni/YSZ (Yttrium Stabilized Zirconia), another is sulphur poisoning (build-up of sulphur). However, promising results have recently been obtained by swapping to Cu/CeO 2 . This is not susceptible to coking, and is more tolerant to sulphur (He et al. Electrochem Sol Stat Lett 8 A279 (2005)), though sulphur build-up still occurs gradually. We would like to analyse why Cu/CeO2 is more sulphur tolerant, but also how the build-up occurs and how it might be prevented. For pure ceria surfaces it is known (Lu et al. Phys. Chem C, 116, 8417 (2012)) that adhered sulphur atoms (adatoms) are stable, and rather immobile, and the poisoning pathways from various sulphur bearing molecules have been studied, but there are indications (Lu, private communication) that this may be modified by the presence of Cu. Certainly sulphur is more stable on the surface of near-by Cu parts of the composite. This indicates that the sulphur poisoning mechanism may be different from that presumed earlier, and also that suitable modification of the interface (eg doping of one or other component) may provide a way to reduce or overcome the poisoning. Another key application of Cu/CeO 2 interfaces is in catalysis, for example in “three way” catalytic vehicle exhaust converters and potential new H 2 fuel production catalysts, such as for the water-gasshift reaction. A key process in both is the oxidation of CO molecules, while for likely related reasons Cu/CeO 2 anodes in SOFCs have an observed resilience to CO. Meanwhile, oxidation of hydrocarbons is the basis of SOFCs and second key process in three way catalysis. If alloying of SOFC anodes turns out to be advantageous for sulphur tolerance, then its effect on the central processes of fuel oxidation must also be examined. In this project we will therefore go beyond existing studies of pure ceria or Cu surfaces, using DFT to study the physics and chemistry of the Cu/CeO 2 interface in much greater depth than before. We will look at the stability of sulphur and sulphur bearing molecules at this interface, as well as the interaction of CO and example fuels with it. After this we will look at the effect of adding (“doping” or “alloying”) with other metals to the materials. Can this be used to influence or control the key interactions, and if so can we make specific practical recommendations on improving the devices? Day-to-Day Activities: This kind of research can be viewed as a kind of virtual experimentation, and has been described as being a virtual microscope with atomic scale precision. This difference is that we also have complete control over the atoms themselves, and can study not only the lowest energy structures, but also the processes and effects of moving or swapping individual atoms. Each “experiment” therefore starts with deciding which atoms to put where, exactly which properties to calculate, and to what level of accuracy. The calculations then run on local or national scale parallel computing facilities, before analysis of the results: Which material structures are most stable? What states are the electrons in? What are the energy barriers controlling the rates of key processes, etc. Naturally, the project will also involve writing papers … and a thesis. In addition, you will have the opportunity to earn some additional income and gain experience in teaching undergraduates, and will also be involved in collaborations with research groups outside the UK, including groups at Uppsala University, Sweden, and Henan Normal University, China. Entry Requirements, Experience Etc: The formal qualification needed is BSc or MSci degree at 2.1 or above in Physics or Chemistry. Experience of computational physics or chemistry, experience with DFT, or experience of working with or studying fuel cells would be an advantage, but is not a requirement. CONTACT For informal enquiries about [email protected] this project, please contact: Christopher Castleton: This project has been selected for consideration for a fully-funded Vice-Chancellor’s PhD Scholarship at Nottingham Trent University. Fifteen PhD projects will be funded across the University through the Vice-Chancellor’s PhD Scholarship Scheme for entry in 2015/16. Full details of the projects and the competition are available at: http://www.ntu.ac.uk/research/graduate_school/studentships/index.html For information on entry requirements including English Language, details of the award, and how to apply, please see the School information sheet. The closing date for applications is 12.00 noon on Friday 12 December 2014.