Nitrous oxide (N2O, laughing gas) is an abundant gas that accumulates in the Earth’s atmosphere, leading to depletion of ozone in the stratosphere and contributing to global warming as a potent greenhouse gas. Increasing anthropogenic emissions of N2O from intensive agricultural fertilisation, industrial processes and wastewater treatment are a cause for concern due and make it imperative that sustainable methods are developed to remediate concentrated fluxes of this environmental pollutant. Although thermodynamically favourable, abatement by direct decomposition into N2 and O2 is encumbered by the formidable kinetic stability of N2O. Indeed, while heterogeneous catalysts have been developed that promote this reaction thermally, the elevated temperatures required for them to operate effectively render them unsustainable. Photocatalytic variants that harness solar energy are more economically viable alternatives but poorly developed a present. Of the work conducted to date, titanium-oxide based materials have emerged as the most promising targets, benefiting from the low cost, high Earth abundance and non-toxic nature of titanium. To advance the development of new and more effective titanium-based photocatalysts, this project will explore the photochemically–promoted decomposition of N2O mediated by well-defined dinuclear titanium complexes supported by bespoke ligand architectures (Figure 1). This work will build upon breakthrough findings in the Chaplin group, involving development of transition metal catalysts for the hydrogenation and deoxygenation of N2O, and exploit expertise of the Pike group for harnessing photoredox reactivity of titanium-oxo clusters.
Figure 1: Photochemical promoted nitrous oxide decomposition mediated by titanium.
This project is not suitable for CASE funding
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A design strategy based on dinuclear titanium-oxo catalysts will be systemically evaluated during the project, with a focus on the reactivity and catalytic activity of well-defined systems supported by photostable chelating ligands (Figure 1). Ligands of varying complexity will be assessed over the course of the project and the most active systems optimised, guided by mechanistic insights and emerging structure-activity trends, to maximise activity for the photocatalytic decomposition of N2O. This work will benefit from the combined expertise of the Chaplin and Pike groups, the extensive range of the state-of-the-art analytical facilities available onsite at Warwick, and regular access to bespoke facilities at the Diamond Light Source to perform experiments that enable photoinitiated reactions to be studied in crystallo.
DRs will be awarded CENTA Training Credits (CTCs) for participation in CENTA-provided and ‘free choice’ external training. One CTC can be earned per 3 hours training, and DRs must accrue 100 CTCs across the three and a half years of their PhD.
This project will provide exceptional interdisciplinary training spanning advanced methods for, the synthesis and manipulation of air and moisture sensitive compounds, quantitative analysis of catalytic reactions using gas chromatography, and characterisation of open-shell compounds in solution and the solid state. Hands-on use of diffraction methods will be an integral part of the project, with collection and analysis of single crystal X-ray diffraction data collected in house and at central facilities a key focal point. Training will be provided throughout by the supervisors and senior members of their research teams.
Results from the project will be used to engage with relevant industries, working with the University of Warwick’s technology transfer office (Warwick Innovations) to review and protect any emerging Intellectual Property.
Year 1: Synthesis and characterisation of dinuclear titanium-oxo complexes, with a focus on systems featuring simple chelating ligands. Proof-of-principle reactions of titanium(III) derivatives with N2O and preliminary photocatalytic studies.
Year 2: Preparation and catalytic evaluation of titanium-oxo complexes stabilised by dinucleating and macrocyclic ligand platforms. Detailed mechanistic studies and compilation of structure-activity trends for the photocatalytic decomposition of N2O.
Year 3 and 4: Mechanism-lead optimisation of the most active catalysts. Stability and operational testing using dilute concentrations of N2O and in the presence of air.
S. H. Dewick, T. M. Hood, Y. Han, S. Huband, A. B. Chaplin, “Rhodium-catalysed hydrogenation of nitrous oxide” Catal. Sci. Technol. 2025, 15, 4126–4129. https://doi.org/10.1039/d5cy00490j
T. M. Hood, R. S. C. Charman, D. J. Liptrot, A. B. Chaplin, “Copper(I) Catalysed Diboron(4) Reduction of Nitrous Oxide” Angew. Chem. Int. Ed. 2024, e202411692. https://doi.org/10.1002/anie.202411692
S. E. Brown, M. R. Warren, D. J. Kubicki, A. Fitzpatrick, S. D. Pike, “Photoinitiated Single-Crystal to Single-Crystal Redox Transformations of Titanium-Oxo Clusters” J. Am. Chem. Soc. 2024, 146, 17325–17333. https://doi.org/10.1021/jacs.4c04068
X. Wu, J. Du, Y. Gao, H. Wang, C. Zhang, R. Zhang, H. He, G. (Max) Lu, Z. Wu, “Progress and challenges in nitrous oxide decomposition and valorization” Chem. Soc. Rev. 2024, 53, 8379–8423. https://doi.org/10.1039/d3cs00919j
S. E. Brown, I. Mantaloufa, R. T. Andrews, T. J. Barnes, M. R. Lees, F. D. Proft, A. V. Cunha, S. D. Pike, “Photoactivation of titanium-oxo cluster [Ti6O6(OR)6(O2CtBu)6]: mechanism, photoactivated structures, and onward reactivity with O2 to a peroxide complex” Chem. Sci. 2022, 14, 675–683. https://doi.org/10.1039/d2sc05671b
K. Severin, “Synthetic chemistry with nitrous oxide” Chem. Soc. Rev. 2015, 44, 6375–6386. https://doi.org/10.1039/c5cs00339c
Before starting the project, applications must hold an honours degree (at least 2.1 or equivalent) in Chemistry, or other relevant discipline.
Enquires are welcomed and applications should be directed to Professor Adrian Chaplin ([email protected]); please include a current CV that details any past research work.
To apply to this project:
Applications must be submitted by 23:59 GMT on Wednesday 7th January 2026.