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.