- The project aims to address the remediation of greenhouse gases, specifically focusing on the decomposition of nitrous oxide (N2O).
- The studentship will explore photochemical promoted heterogeneous catalysis, harnessing solar energy to enhance the catalytic activity of metal oxide materials. This approach offers potential for mitigating N2O emissions and reducing its impact as a potent greenhouse gas.
- Working collaboratively with supervisors and project partners, the student will develop various catalyst targets. This will foster innovation and creativity in catalyst design, contributing to the advancement of sustainable solutions for greenhouse gas remediation.
Overview: Nitrous oxide (N2O) is a potent greenhouse gas, with a global warming potential 300 times greater than carbon dioxide, and the dominant ozone depleting substance emitted in the 21st century. Although naturally occurring, increasing anthropogenic N2O emissions from intensive agricultural fertilisation, industrial processes, and combustion of fossil fuels and biomass are a major cause for concern due to the detrimental impact this will have on our environment. The selective decomposition of N2O into environmentally benign N2 and O2 is a compelling prospect to remediate such emissions but, despite being a thermodynamically favourable reaction, activation of this weakly interacting triatomic gas is encumbered by a considerable degree of kinetic inertness. The overarching aim of this project is to harness solar energy to promote this reaction, using thermally and industrially relevant metal oxide materials as catalysts.
Methodology: Decomposition of N2O can be promoted thermally using metal oxides but typically requires temperatures >400 °C that are not desirable from a remediation perspective. Photocatalytic alternatives that harness solar energy are attractive and potentially viable alternative but are poorly developed. This project will explore this possibility and involve (a) synthesis of established and novel metal-oxide-based photocatalysts, (b) development of analytical procedures for accurately evaluating N2O decomposition reactions under different regimes (pure N2O, N2O and inert gas mixtures, and dilute N2O in air), and thereafter (c) systematic evaluation of the photocatalysts for N2O decomposition. Precisely monitoring the decomposition of N2O into N2 and O2 is considerable analytical challenge, and a range of techniques will be explored to determine which is best for a given reaction regime. The use of quantitative head space sampling by gas chromatography will be fully explored in combination with FTIR-based methods.
Training and skills: This PhD project will provide exceptional interdisciplinary training. In addition to the analytical techniques highlighted above, the student working on this project will develop methods for the synthesis and characterisation of technologically relevant solid-state materials; the latter benefiting from the extensive range of analytical techniques available at Warwick such as X-ray diffraction, thermal analysis, and microscopy, with the possibility of developing operando versions of these to understand the mechanism of catalysis and stability of catalysts.
Year 1: Synthesis of established metal-oxide-based photocatalysts; optimisation of analytical procedures for analysing gaseous mixture of N2O, N2, and O2; analysis of established metal-oxidebased photocatalysts for the decomposition of pure N2O.
Year 2: Iterative preparation, catalytic evaluation, and mechanistic investigation of novel metal-oxidebased photocatalysts for the decomposition of pure N2O and inert gas mixtures of N2O. N2O N2 + ½O2 hν Heterogeneous metal oxide catalyst
Year 3: Continued iterative preparation, catalytic evaluation, and mechanistic investigation of novel metal-oxide-based photocatalysts for the decomposition of inert gas mixtures of N2O, and increasingly dilute mixture of N2O in air.