Plasmonic enhancement of hydrogen from water: experiment and theory

The surface plasmon resonance of nanostructures enhances solar light harvesting in one of several
ways, namely photo-induced charge transfer, near-field enhancement, or scattering. The actual
mechanism has still to be determined; this is the research question. It has been shown that the
plasmon resonances of Au and Ag nanoparticles can typically shape dependent. It is therefore of
interest to be able to control the shapes of nanoparticles.
TiO2 surfaces are used as model systems to understand the fundamental mechanisms of
photocatalysis. The first aim of this project will be to investigate the shapes of Au nanoparticles
grown on TiO2 by characterisation with scanning tunnelling microscopy (STM). In particular, the
project will examine whether Au nanowires can be grown by physical vapour deposition on rutile
TiO2(110), similar to Pd nanoparticles. Characterisation of photocatalysis will employ molecular
adsorbates such as H2O and OH. This will be carried out using scanning tunnelling spectroscopy,
high resolution electron energy loss spectroscopy as well as XPS, UPS. These measurements will be
used to probe the surface before and after plasmonic enhancement using laser excitation of the
nanoparticles. Varying the laser power and frequency as well as observing the directionality of the
plasmonic response will shed light on the active mechanism of plasmonic enhancement of
photocatalysis.

The production and processing of materials accounts for 15% of UK GDP and generates exports valued at £50bn annually, with UK materials related industries having a turnover of £197bn/year. It is, therefore, clear that the success of the UK economy is linked to the success of high value materials manufacturing, spanning a broad range of industrial sectors. In order to remain competitive and innovate in these sectors it is necessary to understand fundamental properties and critical processes at a range of length scales and dynamically and link these to the materials' performance. It is in this underpinning space that the CDT-ACM fits.

The impact of the CDT will be wide reaching, encompassing all organisations who research, manufacture or use advanced materials in sectors ranging from energy and transport to healthcare and the environment. Industry will benefit from the supply of highly skilled research scientists and engineers with the training necessary to advance materials development in all of these crucial areas. UK and international research facilities (Diamond, ISIS, ILL etc.) will benefit greatly from the supply of trained researchers who have both in-depth knowledge of advanced characterisation techniques and a broad understanding of materials and their properties. UK academia will benefit from a pipeline of researchers trained in state-of the art techniques in world leading research groups, who will be in prime positions to win prestigious fellowships and lectureships. From a broader perspective, society in general will benefit from the range of planned outreach activities, such as the Mary Rose Trust, the Royal Society Summer Exhibition and visits to schools. These activities will both inform the general public and inspire the next generation of scientists.

The cohort based training offered by the CDT-ACM will provide the next generation of research scientists and engineers who will pioneer new research techniques, design new multi-instrument workflows and advance our knowledge in diverse fields. We will produce 70 highly qualified and skilled researchers who will support the development of new technologies, in for instance the field of electric vehicles, an area of direct relevance to the UK industrial impact strategy.
In summary, the CDT will address a skills gap that has arisen through the rapid development of new characterisation techniques; therefore, it will have a positive impact on industry, research facilities and academia and, consequently, wider society by consolidating and strengthening UK leadership in this field.