Available PhD Projects
Low-energy-footprint photocatalysis for H2 Evolution
Bath Monash Global PhD Programme in Sustainable & Circular Technologies
(Competition Funded PhD Project (UK Students Only) – Deadline 30th January 2022
This PhD is based at the University of Bath, with a 12-month stay in Melbourne at Monash University.
The catalytic conversion of sustainable molecules into value added chemicals is a key enabling technology in the transition to a sustainable chemical sector. Catalytic materials based on nanoparticles (NPs) of Cu, Ag and Au (5 – 50 nm) have been widely deployed in selective reduction and oxidation processes, however, often require harsh conditions (high temperature / pressure) to pre-activate the catalysts or to perform the reactions of interest.
Cu, Ag and Au NPs show strong light absorption by surface plasmon resonance, allowing energy to be deposited directly into the catalytic sites using visible light – rather than thermal conduction through large solvent volumes from heated reactor walls. When plasmons decay in metal nanostructures, highly energetic electron/hole pairs are generated, with Fermi temperatures on the order of thousands of Kelvin. A few picoseconds later, this energy has equilibrated with the lattice, raising the local temperature in the particle. Both of these processes — hot charge carriers and raised temperatures — show great promise in overcoming activation barriers for catalysis.1 The project will look to develop plasmonic catalysts that can release H2 from bio-derived molecules through acceptorless dehydrogenation reactions which are highly endothermic and therefore require elevated temperatures. Our aim is to reduce the thermal energy used to heat large reaction volumes and to develop the relationship between light absorption/catalytic structure/performance.
We will investigate these plasmonic photocatalytic processes via a comprehensive PhD project involving materials synthesis and reactivity evaluation (Freakley, Marken – Bath ), electromagnetic modelling and nanooptical and redox activity mapping of plasmonic nanostructures (Maier, Bentley – Monash). In Monash we will employ the recently established high-resolution scanning electrochemical cell microscopy (SECCM) platform to probe the redox activity of individual nanostructures immobilized onto supporting electrodes. Information from SECCM will then be related to NP structure and properties, obtained from co-located microscopy/spectroscopy facilities, allowing the underlying structure−property relationships to be established.
Supervisors at Bath: Dr Simon Freakley, Prof Frank Marken (Chemistry)
Supervisors at Monash: Dr Cameron Bentley (Chemistry), Prof Stefan Maier (Physics & Astronomy)
To find out more about the project please contact: Dr Simon Freakley
Hot Electrons and Polaritons Science
Imperial College London
Optical nanostructures of metal or dielectric materials can support extremely large optical intensities of light. This is extremely useful for sensing applications – approaching single molecule level sensitivity. A side effect is the generation of heat due to absorption, which was thought to be a disadvantage but recently it was realised that this could enable chemical reactions. The absorption processes generate “hot” electrons that can significantly influence physical and chemical processes near interfaces; not (only) as a result of the high electric fields, but also from the transfer of these energetic electrons to adjacent molecules or materials. This paradigm now allows photo-chemical reactors for water splitting and CO2 reprocessing, for example. At the same time, the interaction of the molecule with the metal particle, and with nanocavities in general, can profoundly alter the energetic states of the molecule, via the formation of a polariton.
The aim of this PhD project is to understand the physics and harness applications associated with such “hot” electron processes and molecular energy shifts, induced by photo-absorption in designer nanostructures constructed from a new breed of materials. This will open new paradigms in ultrafast control over nanoscale chemical reactions switchable with light, optically controlled catalysis, optical and electric processes in semiconductor devices induced by plasmonic hot-electrons, integration with two-dimensional materials such as graphene, as well as nanoscale metrology tools for temperature and field measurements.
Follow this link to find information of how to apply:
Information about postgraduate studies in the EXSS Group at Imperial College London