CINE WEBINAR: "The solar driven synthesis of sustainable fuels: photochemistry"

Materials research is central to the development of many sustainable energy technologies. I will start my talk by introducing this broad challenge of materials for sustainable energy, and research within the Centre for Processable Electronics at Imperial addressing this challenge.

My talk will focus on the particular challenge of the solar driven synthesis of fuels and chemicals, and its potential role in reducing our dependence on fossil fuels. I will briefly review approaches to artificial photosynthesis, and the lessons which can be learnt from biological photosynthesis, as well as challenges and opportunities for photovoltaics plus electrolysis. I will then go on to introduce my own particular research interest, the role of charge carrier dynamics in determining the efficiency of such systems, focusing on photocatalysts and photoelectrodes for water oxidation and reduction, as well as electrocatalyst kinetics.

I will primarily focus on metal oxide materials, although also covering organic polymer photocatalysts and hybrid molecular / inorganic systems for solar driven proton and CO2 reduction. Experimentally, these studies will be based around transient absorption spectroscopy on timescales from femtoseconds to seconds, including operando spectroelectrochemical studies, which will be correlated with the results of (photo)electrochemical analyses of device efficiency. These studies will address the dynamics of charge separation and recombination, as well as the kinetics of water oxidation / reduction at semiconductor / liquid interfaces. Issues which will be addressed will include the underlying photochemistry of oxides, the role of the space charge layers at electrochemical junctions in spatially separating charges, the role of heterojunctions and catalysts layers in enhancing system efficiency, and electrocatalyst kinetics. Particular consideration will be placed on the kinetics of catalysis, and the extent to which metal oxides accumulate reactive states which drive the multi-redox chemistry required for water oxidation and reduction.