PhD cohort 3

Department of Chemistry/Department of Physics

Supervisor: Professor James Durrant and Dr Piers Barnes 

Funder: ESPRC (as part of the ATIP Grant) 

Summary of project:

Halide perovskites are a class of next generation photovoltaic (PV) materials which have achieved Power Conversion Efficiencies (PCEs) above 25%. This is comparable to the performance of single-crystal silicon PVs. However, the best halide perovskite devices suffer from stability issues which limit their operative lifetime. Further research is needed to understand what mechanisms are responsible for the high PCEs of halide perovskites. This will allow for the design of systems which maintain high efficiencies while also achieving a lifetime which is suitable for commercial applications.  

My project will investigate the effect of trap states on the charge dynamics of halide perovskite solar cells. Halide perovskites are observed to contain a high density of trap sites compared to other inorganic PV materials. As electrons (holes) become localised by traps and can only return to the conduction (valance) band by overcoming an activation barrier, traps generally cause a decrease in carrier mobility. The focus of my PhD will be to gain a better understanding of the impact that these traps have upon device PCE using a combination of transient optoelectronic measurements and computational modelling. 

Environmental Research Group, School of Public Health 

Supervisors: Dr Heather Walton, Dr Rachel Smith, Dr Karen Exley 

Funder: NIHR HPRU in Environmental Exposures and Health

Project Summary: 

An increasing number of studies suggest the association between exposure to ambient air pollution and the risk of preterm birth. Yet, results from these studies are inconsistent. To address the need for high quality, up-to-date summary of the evidence, the first step of this project involves conducting a systematic review and meta-analysis, including recent studies with more sophisticated methodologies. Afterwards, this project aims to develop a concentration-response function that can benefit policy analysis. A health impact assessment will subsequently be conducted to link epidemiological research and risk assessment studies.

Department of Earth Science and Engineering

Supervisor: Dr Pablo Brito-Parada

Funder: EPSRC (Engineering and Physical Sciences Research Council)

Project summary: 

The decrease in conventional oil supply (production+imports) since 2006, and that of natural gas since 2005 in Europe (EU27+Norway) coupled with the growing problem of climate change are fuelling the search for alternative energy sources, which require much of, if not more than, our limited material reserves to build. The relative size of our material resources compared to the amounts required to satisfy our energy demand via renewable energy technologies will be studied carefully during my project to guide future energy resource developments. More specifically I will study material and energy flows, and methods to account for uncertainties associated to them. The aim of my project is to develop a framework which enables uncertainties and their effects to be well understood, providing more transparent results on which better policymaking can be based. There is a particular focus on the supply and demand of materials relevant to the energy transition which represent the interface between material flow analysis (MFA) and energy system modelling (ESM).

Department of Chemistry

Supervisor: Professor James Durrant

Funder: Department of Chemistry Schrödinger Scholarship

Project summary: 

This PhD project will focus on operando spectroscopic analysis of photoelectrodes for sustainable fuel synthesis. Solar fuels store the sun’s energy in the form of chemical bonds and provide a method of storing and transporting solar energy. The initial focus will be on green hydrogen generation through water splitting, but there is also scope to investigate the application of these systems in the oxidation of other small molecules, such as glycerol, again coupled to green hydrogen generation. The kinetic characterisation of heterojunction systems will be used to understand the function of individual components, with a broader aim of using this to guide the optimisation of system fabrication to maximise sustainability while also optimising photoelectrochemical efficiency. Ultimately, sustainable energy solutions must utilise non-toxic, abundant and cheap materials in order to be viable both economically, and in terms of human and environmental impact. Understanding how photoanodes work on a charge carrier level is crucial to achieving this goal.

School of Public Health

Supervisor: Professor Mireille B Toledano

Funder: NIHR HPRU in Chemical and Radiation Threats and Hazards

Project summary:

The Breast Milk, Environment, and Early-life Development (BEED) study was established to address public health concerns about the relationship between modelled area level ambient dioxin exposure and individual level breast milk dioxin exposures. The study recruited primiparous pregnant women living near three municipal waste incinerators in England to gain detailed exposure profiles, the participants provided breast milk samples as well as lifestyle and diet information. This PhD project will utilise results from this study to investigate the relationship between milk dioxin levels and modelled ambient dioxin concentrations, by dioxin congener and modelled zone. This will lead into the opportunity to explore relationships between metabolomic and neurodevelopment outcomes and individual exposure to dioxins, furans and heavy metals.

Department of Civil and Environmental Engineering

Supervisor: Dr Ana Mijic

Funder: Department of Civil and Environmental Engineering Dixon Scholarship; China Scholarship Council

Project summary: 

According to UN-Water 2021, 21 million people, including 5 million children, live within 5 km of polluted water bodies with high turbidity. Whether to facilitate regulation, to plan for the future or to manage the present, the predictions provided by water systems model are essential. This PhD project will develop representation of open water bodies (OWBs, wetlands include lakes and reservoirs) in the systems ‘CatchWat’ model under development in Dr Ana Mijic’s Water Systems Integration (WSI) group to facilitate a generalisable and integrated view of OWBs as part of the water cycle. The research will also represent the interaction between quality and quantity of water in wetlands with biodiversity and leveraging this representation to design urban- and rural-scale interventions to biodiversity improvement. Link to TZP will be around assessing ecological impacts and how we can use natural and constructed wetland systems to minimise pollution and damage. We hope to build a sustainable zero pollution future from the perspective of water cycle.

Centre for Environmental Policy

Supervisor: Dr Morena Mills

Funder: Engineering and Physical Sciences Research Council (EPSRC)

Project summary:

Natural systems such as forests or wetlands improve air and water quality while providing a host of co-benefits such as carbon storage, flood protection or wildlife habitat. The persistence of natural systems and the services they provide to humanity depends not only on habitat protection, but also on large scale ecosystem restoration. This interdisciplinary PhD project studies the factors driving the adoption, spread and abandonment of woodland expansion interventions in the UK, as well as on how to optimise the deployment of these interventions in space. The main objective is producing key insights to inform the design, priorities and delivery of future ecosystem restoration efforts to maximise environmental and social benefits and minimise costs. Contributing to unleash the huge potential of ecosystem restoration to address the current global environmental crises and enhance biodiversity and human well-being. 

Department of Earth Science and Engineering 

Supervisors:  Professor Dominik Weiss and Dr Yves Plancherel 

Funder: Royal Thai Government

Project summary:

Bangkok Thailand, continues experiencing an unhealthy air pollution level caused by particulate matter (PM) from diesel engine exhaust emissions and agricultural activities. It is clear that some trace elements in PM are toxic, such as heavy metals. During a rainfall, PM particles can be attached to the surface of a raindrop. This process can reduce air pollution, but it might increase pollutant trace element concentrations in wet deposition. As Bangkok is surrounded by a large agricultural area, the pollutant trace elements might be accumulated in the soil and be taken up by cultivated plants, such as rice.

This project aims to develop an understanding of the environmental footprint of the pollutant trace elements in Thailand, including an evaluation of the pollutant trace element cycle, characterisation of the role of anthropogenic emissions and quantification and tracking of pollutant trace elements into the agriculture sector of Thailand.

Department of Chemical Engineering

Supervisors: Prof Magda Titirici, Dr Ifan E. L. Stephens, Prof Mary Ryan

Funder: Royal Academy of Engineering

Project summary:

Ammonia’s extensive use in the fertilizer industry made it a key component of global human wealth and food supply. Unfortunately, it is currently mass-produced via the Haber-Bosch process, releasing 400 MtCO₂ annually in the atmosphere, being responsible for 1.5% of CO₂ human emissions. Electrochemical nitrogen reduction reaction (NRR) emerged as an alternative to this process. Using only H⁺ and N₂ for feedstock and alleviating renewable electricity as an energy input provides a more sustainable route to NH₃. Additionally, this may offer a means for renewable energy storage.

This PhD project aims at improving NRR’s currently low efficiency by eliminating its competing side-reaction: direct proton reduction to H₂. Inspired from battery science, we hypothesize that upon partial electrolyte decomposition, a stable interphase forms between the electrode catalyst and the electrolyte. By tailoring the electrolyte, thus the interphase, one may alter protons access to the catalyst surface, hindering their direct reduction to hydrogen, rather being used for NRR.

Department of Materials

Supervisor: Professor Milo Shaffer

Funder: Department of Materials DTP

Project summary: 

My project aims to optimize a novel aerogel composite, to design a prototype of a simple and ultra-low-cost Direct Air Capture (DAC) system. Generally, DAC is the sequestration of carbon dioxide CO₂ from our ambient atmosphere, in which adsorption processes capture CO₂ using liquid or solid-state sorbent materials. The regeneration processes of typical thermal and pressure-swing desorption strategies tend to be elaborate, energy-intensive, and thus expensive per tonne of captured CO₂. The premise of my project is to achieve efficient ad/desorption to functional groups decorated across the aerogel's high specific surface area, wherein an applied bias drives the desorption cycle via joule-heating: an electro-swing process.

The captured CO₂ can then be stored underground or used in the production of near carbon-neutral structural materials and fuels. The integration as a more holistic climate mitigation strategy will consider the use of renewable intermittent power sources, the scalability of DAC ‘farms’, and the end product of the captured carbon.