Why make oxygen when you could make useful chemicals instead?

Solar-driven fuel synthesis is a sustainable and potentially economical technology for producing energy carriers such as “green” H2 fuel through water splitting. Photocatalytic water splitting processes are usually limited by the water oxidation half-reaction, which is kinetically and energetically demanding as well as requires often expensive catalysts and unsustainable sacrificial reagents. Our research aims to overcome these challenges by using alternative oxidation half-reactions to drive the breakdown of waste polymers or chemicals into valuable organic products. We utilise a variety of novel photocatalysts – including quantum dots and carbon-based nanomaterials – to (1) develop light-driven, high-yield organic transformations and (2) “photoreform” plastic- or biomass-derived waste into organics and fuel. Our aim is to enhance the sustainability and economic value of solar fuels by developing processes that simultaneously produce fuels and drive value-added organic transformations.

Selected Publications

Why release CO2 into the atmosphere if you could use it to make fuels and chemicals?

The sustainable utilisation of the greenhouse gas CO2 represents a key step towards accomplishing a circular carbon economy. To address this goal, we interface light absorbers with suitable catalysts for the light-driven conversion of CO2 to value-added chemicals, including CO, formate, methane, or liquid multicarbon products. Our research covers various facets of CO2 conversion, from fundamental studies on electrocatalytic surface-bound interactions, to applied research on device integration and upscaling. Molecular catalysts are immobilised onto nanostructured metal oxide, lead halide perovskite, and silicon semiconductors to promote highly-selective CO2 conversion in both aqueous and organic media. Spectroelectrochemical studies on those (photo)electrodes uncover mechanistic insights into optimal catalyst loading and selectivity. Synthetic catalysts are functionalised with a variety of anchor groups to enable photocatalysis in colloidal systems involving quantum dot, carbon nitride and carbon dot nanoparticles. Photoelectrochemical “artificial leaf” devices and particulate photocatalyst sheets are being developed to probe the stability and scalability of our systems, taking practical aspects as variable daylight conditions and day-night cycles into account. Overall, our efforts strive towards establishing solar carbon fuels as a competitive alternative to fossil fuels in the future.

Selected Publications

Why not combine the best of materials science and biology to develop new concepts for solar energy conversion?

Semi-artificial photosynthetic systems aim to overcome the limitations of natural and artificial photosynthesis while providing an opportunity to investigate their respective functionality. Enzymes are macromolecular biological catalysts that have been naturally selected over billions of years to perform specific reactions with high selectivity and efficiency. In particular, we are interested in interfacing photosynthetic and redox active enzymes with custom-made high surface area electrodes to study their fundamental biology and drive interesting endergonic reactions. In parallel, we examine how more complex living microorganism systems can be recruited for in vivo fuel and chemical production.

Our lab employs a suite of chemical biology and biophysical methods, including advanced (photo)electrochemical techniques such as rotating ring disk electrochemistry, resonance Raman and infrared spectroscopy and quartz crystal microbalance measurements. To develop enzyme and cell-based hybrid (photo)electrochemical devices with light absorbing semiconductors such as metal oxides, perovskites and silicon we design high-surface area electrode materials, such as metal oxides, carbon nanotubes and graphene as conductive supports with high loading. We also study photocatalytic systems with semiconducting nanoparticles such as carbon dots, graphitic carbon nitride and quantum dots for hybrid solar fuel generation in suspension.

Selected Publications