PhD Studentship: Atmospheric Chemistry of Hydrofluoroolefins: Spectroscopic and Computational Studies of Fluorinated Criegee Intermediates

Hydrofluoroolefins (HFOs) are a new generation of refrigerants designed as environmentally friendly replacements for older halocarbons. They have very low global warming potential and zero ozone depletion potential, leading to their rapid adoption in commercial and domestic systems, such as automotive air conditioning and heat pumps. Global emissions of HFOs are projected to exceed one million tonnes annually by 2050, primarily in densely populated regions. Despite their growing use, the atmospheric breakdown of HFOs is poorly understood. Once released, they are oxidised to form potentially hazardous products such as carbonyls, secondary organic aerosols (SOA), and trifluoroacetic acid (TFA), a persistent “forever” chemical with implications for air quality, health, and climate.

A particularly important but underexplored process is the ozonolysis of HFOs, especially at night when photochemical oxidants like OH are absent. Ozonolysis of alkenes generates highly reactive Criegee intermediates (CIs), which are now known to be key drivers of radical and particle formation in the atmosphere. However, the chemistry of fluorinated Criegee intermediates (HFO-CIs) has scarcely been studied. Their potential to form toxic oxidation products, drive SOA growth, and influence tropospheric oxidative capacity represents a major knowledge gap.

This studentship will focus on fundamental laboratory and computational studies of HFO-CIs, providing the first direct spectroscopic detection of their structures, reaction rates, and branching ratios with common atmospheric species. Experiments will be conducted using cutting-edge laser techniques uniquely capable of selective detection of trace reactive intermediates. In parallel, high-level quantum chemical calculations and master-equation modelling will characterise the reaction pathways and provide insights into conformer-specific reactivity.

The results will be incorporated into the Master Chemical Mechanism (MCM), the international benchmark for atmospheric modelling, and applied in urban air quality scenarios (e.g. Beijing, Delhi) to assess the wider impacts of HFO chemistry on oxidative budgets, ozone formation, and aerosol production. This interdisciplinary project bridges laboratory spectroscopy, computational chemistry, and atmospheric modelling, offering the student a unique opportunity to contribute to a pressing environmental challenge at the interface of physical chemistry, climate science, and public health.

For further information on this project and details of how to apply to it, please click on the 'Apply' button above.

Further information on how to apply for a CENTA studentship can be found on the CENTA website: https://centa.ac.uk/apply/

Funding notes:

This project is offered through the CENTA3 DLA, funded by the Natural Environment Research Council (NERC). Funding covers: annual stipend, tuition fees (at home-fee level), Research Training Support Grant.

Academic requirements: at least a 2:1 at UK BSc level or a pass at UK MSc level or equivalent.

International students are eligible for studentships to a maximum of 30% of the cohort. Funding does not cover any additional costs relating to moving or residing in the UK. International applicants must fulfil the University of Birmingham’s international student entry requirements, including English language. Further information: https://www.birmingham.ac.uk/postgraduate/pgt/requirements-pgt/international/index.aspx.

References:

Journal:

Holland, R. et al (2021) Investigation of the Production of Trifluoroacetic Acid from Two Halocarbons, HFC-134a and HFO-1234yf and Its Fates Using a Global Three-Dimensional Chemical Transport Model. ACS Earth and Space Chemistry, 5, 849-857. Doi: 10.1021/acsearthspacechem.0c00355

Andreae, M. O. (2013). The Aerosol Nucleation Puzzle. Science, 339, 911-912. Doi:10.1126/science.1233798

Watson, N. A. I. & Beames, J. M. (2023). Bimolecular sinks of Criegee intermediates derived from hydrofluoroolefins – a computational analysis. Environmental Science: Atmospheres, 3, 1460-1484. Doi: 10.1039/D3EA00102D 

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