Interface Engineering for Solar Fuels

The use of fossil fuels and resulting CO2 emissions are exacerbating global climate change. The alternative use of hydrogen could cut CO2 emissions and improve air quality of urban areas, since burning hydrogen generates harmless water. To realise this potential we need to find clean ways to produce hydrogen fuel. Water splitting into hydrogen (and oxygen) can be achieved cleanly with electrolysers running on electricity from renewable sources such as solar, wind or hydropower. In a more direct manner, water can also be cleanly split using sunlight and semiconductor absorbing layers integrated in photoelectrodes of photoelectrochemical (PEC) cells. PEC solar water splitting is limited by both poor lifetime of photo-induced charges and poor catalytic properties of semiconductor surfaces to split water at the electrolyte interface.

This fellowship aims to develop novel approaches to engineer the interface between semiconductors and electrolytes, in order to optimise the performance of the semiconductors and achieve efficient solar energy devices. We will develop fabrication methods to tune those interfaces and boost their PEC final performance. Photoelectrodes will be prepared oriented and with exposed active crystal facets, or with extra layers on their surface to mediate with aqueous electrolytes. A systematic approach involving novel syntheses, advanced electrochemical characterisation and solar water splitting performance tests will be carried out to establish the optimal conditions for the formation of photoelectrodes and the characteristics which make them better performing. Finally, best photoelectrodes will be integrated in tandem cells for more efficient solar water splitting.

Preparing semiconductors with engineered interface will have a considerable impact on the research of (photo)electrochemistry, photocatalysis, photovoltaics and on their energy application. This will ensure important advances towards a more sustainable energy mix of clean energy for current and future generations.

Our society will be the main beneficiary from this research. With our current world population doubling every 60 years, depleting fossil sources and global warming, we need to undertake a complete move to renewable energy sources such as wind and solar. This research fellowship programme will participate in this revolution by leading the discovery and development of next-generation materials and devices that efficiently provide clean fuels and feedstocks from abundant sources. We will research and deliver materials for the production of hydrogen fuel from sun and water, creating foundational knowledge to develop a disruptive technology of future solar devices with the potential to convert any waste to useful fuels and feedstocks. These devices will be so powerful one day that if used to convert one Olympic swimming pool of water into hydrogen and oxygen per second, 43 TW of power would be obtained per year, more than double the current world energy consumption.

To benefit society from these future materials and devices, we will also contribute to increasing public awareness on future renewable energy technologies, to facilitate future implementation of these novel technologies. We will train students on topics relevant to these solar devices which will be potential employees in future companies developing such technologies. We will also participate in public engagement events such as Bath Taps into Science, The Bath Science Café, press releases, and public communication in media channels to further disseminate our work in lay terms, making it more accessible to the public.

More specifically, companies in the energy field such as Ceres Power and Advanced Fuel Technologies and research centres such as SPECIFIC will benefit from the novel syntheses developed to prepare better performing photoelectrodes and from the knowledge generated, including complete electrochemical and physical characterisation of the materials and their performance. In addition to solar energy devices capable of producing hydrogen and other fuels, companies will also be able to apply our achieved knowledge in the development of fuel cells for hydrogen cars, electrolysers for hydrogen-fuel enrichment, and solar cells for electricity, boosting their efficiencies. We have agreed a series of meetings with these companies and moreover the researchers of this fellowship will participate in public events and conferences attended by most companies in the energy field. We will keep engaged with all these companies to ensure transfer of knowledge and to gain important insights into market trends and areas where specific current research is needed. We will also work towards developing future partnerships to exploit and develop the discoveries of this research fellowship further, using our Research & Innovations Services office.

The general public will benefit from this research with next generation materials that produce chemical commodities from simply sun and water, diversifying the energy portfolio and feedstocks sources. The results of this research aim to contribute towards a more sustainable society, a circular economy, and a cleaner and healthier environment.