We explore dyes and fuel-forming molecular catalysts immobilised on semiconductors for solar-driven chemical synthesis. By looking at nature for inspiration, we develop new compounds for this purpose and study their properties via various spectroscopic and electrochemical techniques. We subsequently investigate them in combination with electrodes and semiconductor materials developed in our laboratory to achieve solar fuel synthesis through water splitting or CO2 reduction. Structure-activity relationships and mechanistic studies of our immobilised molecular dyes and catalysts allow us to gain an understanding of limiting processes in our hybrid systems. Our aim is to develop new means for low-cost, high-efficiency solar-to-chemical conversion processes.
Our research focuses on applying nanostructured materials for scalable solar energy conversion. We use high-surface area electrode materials, such as metal oxides, carbon nanotubes and graphene as conductive supports for molecular electrocatalysts with high loading. We develop photoelectrodes based on semiconducting materials such as metal oxides, perovskites and silicon which absorb solar light and convert it – with the help of an immobilised catalyst – into fuels such as H2 and CO or value-added chemicals. We also study semiconducting nanoparticles such as carbon dots, graphitic carbon nitride and quantum dots as photocatalysts for solar fuels generation in suspension. Immobilisation of synthetic or enzymatic electrocatalysts with the light absorbing materials combines their favourable photophysical properties such as high extinction coefficients and long excited state lifetimes with the high selectivity of well-defined molecular catalysts.
Enzymes are macromolecular biological catalysts that have been naturally selected over billions of years to perform specific reactions with high selectivity and efficiency. We are interested in interfacing photosynthetic and redox active enzymes with custom-made high surface area electrodes to study their fundamental biology and to drive interesting endergonic reactions relevant to solar fuel and chemical synthesis. We employ a range of chemical biology and biophysical techniques (including ultrafast spectroscopy, vibrational spectroscopy, quartz crystal microbalance) to complement the photoelectrochemical studies.