Full spectrum sunlight to facilitate Carbon Capture and Utilisation

UNSW Chemical Engineers make a breakthrough in their mission to use sunshine to close the carbon loop. 

“Our findings will broaden the scope of catalyst support materials which can effectively activate CO₂. Importantly, the work may inspire new interest in utilising sunlight, an abundant and clean energy source, to facilitate key reactions which require CO₂ activation, such as methanol synthesis.”

Scientia Professor Rose Amal, UNSW Particles and Catalysis Research Group

“To prevent the most serious impacts of climate change, we need to reach net zero emissions by 2050 globally,” says Dr Tze Hao Tan, researcher at UNSW’s globally-recognised Particles and Catalysis Research Group (PartCat).

“But, even if we’re able to achieve this goal, the outstanding carbon dioxide (CO₂) in the atmosphere from fossil fuels burned to date, will continue to warm our planet. Unless we develop methods to remove it, climate change will continue unabated.”

Climate change mitigation is the ultimate goal of many of the pioneering research activities undertaken by PartCat who, in a paper published today in Nature Catalysis called Unlocking the potential of the formate pathway in the photo-assisted Sabatier reaction, detail their latest breakthrough which shows the potential of using the full spectrum of sunlight to facilitate Carbon Capture and Utilisation (CCU).

“CCU is a prime strategy to mitigate climate change and close the carbon loop. By capturing CO₂ and converting it into synthetic fuels and chemicals, we can both reduce emissions and lower the need for fossil fuels,” explains Associate Professor Jason Scott from PartCat.

“Our study is exciting because we have shown the potential of utilising light to facilitate CCU and offset the thermal energy requirements of the reaction. It opens the doorway to using sunlight to drive the process, where it can simultaneously deliver the thermal requirements and the light enhancement effect for the reaction.”

To effectively access the light, the researchers created an innovative catalyst material to activate the CO₂ by modifying the surface of a simple metal oxide with lanthanum oxide.

“For CO₂ to be reactive, particularly at lower reaction temperatures where the light will be most effective, the catalyst has to convert it into a more unstable form,” explains Bingqiao Xie, PhD candidate at PartCat.

“Our modification imbues the metal oxide support with a capacity to convert CO₂ into a form where it can engage the light enhancement effect. We have also identified how light enhancement boosts performance by creating a loop-hole pathway only accessible at low reaction temperatures.”

The elusive phenomena were not detectable using conventional spectroscopic techniques, so the team devised a new method of exploiting the different vibrational frequencies in carbon isotopes to make the observation possible.

Scientia Professor Rose Amal leads the PartCat group and says the findings will open many new doors in the rapidly growing exploration of CCU.

“Our findings will broaden the scope of catalyst support materials which can effectively activate CO₂. Importantly, the work may inspire new interest in utilising sunlight, an abundant and clean energy source, to facilitate key reactions which require CO₂ activation, such as methanol synthesis,” she says.

“It certainly represents a pivotal milestone in our research program to meet the challenges associated with climate change.”

This latest research builds on many years of benchtop material screening and underlying fundamental studies undertaken by the multidisciplinary and diverse team.

“It is our hope that our findings lead to new technologies that tip the status quo, not only helping close the carbon loop but drawing down, and recycling, the excess of problematic CO₂ stuck in our atmosphere,” continues Amal.

Eager to turn their fundamental research into practical solutions, PartCat has already built a solar driven reactor to transform CO₂ into methane on the roof of the Tyree Energy Technologies Building at UNSW. A second, much larger, version of the solar photothermal reactor system is currently being built.

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