Nanotechnology: Fully Funded PhD Scholarship at Swansea University: NanoSense
- Full cost of UK/EU tuition fees, plus a stipend
- 15 March 2020
Nanotechnology: Fully Funded PhD Scholarship: NanoSense: A new generation of low temperature gas sensors based on doping metal oxides with size-selected metal nanoclusters
This scholarship is funded by EPSRC and Alphasense Ltd.
Subject areas: Nanotechnology, surface science
The demand for advanced low cost gas sensors with high sensitivity is currently increasing significantly because of a range of contemporary issues. For example, there is now much greater awareness of the health impacts of outdoor air quality in cities, leading to a need to improve the real time measurement of ozone, CO and NOx emissions at many more locations than currently. The nascent hydrogen economy also requires a network of H2 sensors with a high redundancy factor in order to ensure its safe implementation. Thirdly, the internet of things will require the ability to monitor indoor air quality in houses and cars. Finally, cheap breath sensors could potentially aid in the early detection of a large range of diseases by monitoring specific volatile organic compounds (VOCs). A critical challenge in addressing these important problems is to lower the operating temperature of the gas sensors.
There are many gas detection devices available on the market, ranging from high end optical set-ups with great sensitivity and specificity to cheaper platforms such as electrochemical and chemo-resistive sensors. The latter usually involve a mesoporous layer of a metal-oxide semiconductor such as SnO2 or ZnO, whose resistance is affected by chemical reactions between surface oxygen ions and target molecules (typically hydrocarbons, VOCs, CO, O3, and NOx). They have a high sensitivity, on the order of a few part per million (depending on the target gas) but suffer from poor specificity and a high operating temperature (200-500°C). These issues can be alleviated to some extent by doping the sensing layer with noble metal particles, which act as catalysts for the gas-semiconductor reaction, lowering the optimum temperature towards certain gases. The particles are normally synthesised by wet chemistry and are typically 5 nm or larger in diameter. Catalytic activity has been found to improve dramatically with reduced size.
This project aims to explore much smaller catalyst particles than previously used in semiconductor gas sensors. The fabrication method is cluster beam deposition, as pioneered by the Nanomaterials Lab in Swansea. This technology can fabricate noble metal nanoparticles with atomic precision, from clusters of 3 atoms to a few hundred (thus around 1 nm). These ultra-small clusters have proved very efficient in conventional heterogeneous catalysis but have never been explored in metal-oxide gas sensing. The clusters are also synthesised in vacuum, so they are completely solvent free and devoid of the organic ligands used in aqueous synthesis. This technology has the potential to revitalise the metal oxide gas sensing field, by significantly lowering the operating temperature, leading to lower power consumption, better stability and longer lifetime.
The successful candidate will be initially based at the Bay Campus of Swansea University. The work will involve operating the cluster sources to fabricate size-selected Au and Ag nanoclusters as the catalytic particles for the gas sensing layers and testing the devices using the gas sensing facility. Size-selection will enable even single atom effects to be investigated. The work will be closely informed by the needs of our industrial partner Alphasense, with the aim of improving the operating temperature of their commercial and R&D metal oxide sensors. Eventually, testing of the most promising doping strategies (in terms of cluster size, coverage, cluster beam deposition energy) will be conducted at the Alphasense facilities for direct comparison with industrial gold standards.
Candidates should hold a minimum of an upper second class (2:1) honours degree (or its equivalent) in Engineering or similar relevant science discipline (Physics, Physical Chemistry, Materials Science).
We would normally expect the academic and English Language requirements (IELTS 6.5 overall with 5.5+ in each component) to be met by point of application. For details on the University’s English Language entry requirements, please visit our website for more information.
Due to funding restrictions, this scholarship is open to UK/EU candidates only.
This scholarship covers the full cost of UK/EU tuition fees and an annual stipend of £15,285 for four years.
There will be additional funds available for research expenses.
Please visit our website for more information.
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