New photoreactor design could make sustainable energy more affordable and practical

An international collaboration involving University of Toronto researchers has introduced an innovative model for photoreactors, a solar-powered technology capable of converting water, carbon dioxide, methane, and nitrogen into eco-friendlier chemicals and fuels.

This novel design enables the photoreactor to efficiently capture sunlight from various angles, eliminating the need for sun-tracking mechanisms. The panels can be easily produced using polymer extrusion, ensuring affordability and scalability, thus contributing to a more practical and cost-effective sustainable future.

Geoffrey Ozin, a University Professor in U of T’s chemistry department, along with a team from the Karlsruhe Institute of Technology (KIT) in Germany, spearheaded this project. Solar cells are renowned for converting sunlight into green electricity, reducing reliance on fossil fuels that emit greenhouse gases,” Ozin emphasizes.

In contrast to thermoreactors, photoreactors employ sunlight and reactants to generate environmentally friendly chemicals and fuels. By utilizing sunlight and water, photoreactors hold the potential to effectively decrease carbon emissions.

Despite their promise, several challenges have hindered photoreactor development, including high construction material costs and inefficient photon-to-product conversion. Photoreactors rely on photocatalysts, materials that absorb light and convert reactants into products.

Non-productive processes due to light reflection, scattering, transmission, and absorption by the photocatalyst and photoreactor materials result in energy loss. Sun-tracking devices, which optimize light harvesting by adjusting the photoreactor’s angle with respect to the sun’s position, are often used to mitigate these losses.

For photoreactors to be viable, their photon-to-product conversion efficiency must exceed 10%. While integrating photocatalysts into photoreactors has advanced over the past decade, efficiencies have remained low, often below one percent.

Ozin’s team and KIT researchers, including Paul Kant, Shengzhi Liang, Michael Rubin, and Professor Roland Dittmeyer, developed a panel-like photoreactor featuring numerous parallel microscale reaction channels. Their promising results were published in the journal Joule.

A crucial element of their design involves connecting each reaction channel to a V-shaped light-capture unit, directing light into the channel containing the photocatalyst. All surfaces are highly reflective, minimizing photon losses while optimizing transport from the light source to the photocatalyst in the microchannels.

The inventive design efficiently captures photons without requiring sun-tracking, and the panels can be mass-produced using polymer extrusion, ensuring affordability.

Future iterations of the design could address intermittent sunlight by integrating light-emitting diodes into the photoreactor as the photon source. These LEDs would be powered by renewable electricity from photovoltaics and backed by lithium-ion battery storage for continuous operation.

This new photoreactor model surpasses existing versions and can be installed on rooftops and solar farms, or integrated with photovoltaics to generate renewable electricity and eco-friendly chemicals and fuels.

“This technology has inspired the development of a new generation of solar-powered devices that instead make green fuels such as hydrogen from sunlight and water,” Ozin highlights.

This advancement arrives at a critical moment as combating climate change becomes increasingly urgent, especially considering the record-breaking temperatures observed worldwide this summer.

“These solar products will replace their fossil-based counterparts and contribute to reducing our carbon footprint,” Kant from KIT remarks. “This significantly enhances our chances of achieving sustainable living, and hopefully, we can achieve this in time without severe temperature overshoot and related disasters.”

Leave a Reply

Your email address will not be published. Required fields are marked *