Heriot-Watt University

Solar Fuels

Solar panels

A cross-disciplinary team is applying engineering innovation to increase the efficiency of photocatalytic reduction – a process that uses solar energy to convert carbon dioxide (CO₂) into fuels.

The utilisation of CO₂ as an alternative fuel represents an attractive strategy which addresses the need to reduce the consumption of non-renewable fossil fuels, while also offering sustainable, safe and useful carbon capture. Renewable sources, like solar energy, provide a readily available and continuous light supply for driving the CO₂ conversion process, however, large-scale economic photoconversion of CO₂ into solar fuels represents a formidable scientific and technical challenge. 

The problem is that existing conversion processes do not produce enough fuel to make them financially viable. This is due to a lack of appropriately designed reactors that can efficiently introduce light, reactants and a suitable photocatalyst into simultaneous contact, to produce the necessary separation and recycling of any unreacted CO₂. 

To address this issue, the team is developing new, highly efficient photoreactors. These effectively integrate both mass and light transfer through the optimisation of the physiochemical properties of the catalyst and the reactor's configuration. Utilising advances in nanotechnology, the team is engineering the novel photoreactors using an integrated approach between chemical engineers and chemists to intensify the process of CO₂ photoreduction and increase efficiency and viability.

This new solution offers conversion rates that can be scaled-up to a commercial process. Potentially unlocking a hugely significant source of carbon-neutral fuel, this work creates a technology that could be a genuine game-changer, turning a climate-changing gas into a climate-saving fuel; a process that could offset up to 700 million tonnes of CO₂ each year.