Switchable dual function material captures CO2 in three chemical reactions

The Surrey team’s switchable DFM - NiRuNa/CeAl - consists of nanoparticles of a bimetallic alloy, in combination with a dispersed Na-based adsorbent. These elements are combined to create a unique material for capturing and converting CO2 using three chemical reactions.

The ‘switchable’ nature of the DFMs comes from their ability to produce multiple chemicals depending on the operating conditions or the composition of the added reactant. This makes the technology responsive to variations in demand for chemicals as well as the availability of renewable hydrogen as a reactant. The team’s findings have been published by the Journal of Materials Chemistry A.

In a statement, lead author Dr Melis Duyar said: "Pursuing advanced carbon capture technology is more than just the right thing to do for our planet - it's an exceptional opportunity for the UK to emerge as a global front-runner, leveraging the vast potential of green energy products born from this process.

"We'll continue to apply the lessons learnt from this study and work with others in the higher education sector and industry to continue to mature this process."

Surrey researchers found that NiRuNa/CeAl can be used to capture CO2 in three chemical reactions, namely CO2 methanation, reverse water-gas shift, and dry reforming of methane (DRM).

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CO2 methanation - a process where CO2 is converted into methane - combines CO2 with hydrogen to produce methane (also called ‘synthetic natural gas’) and water.

Reverse water-gas shift is a chemical process involving the conversion of CO2 and H2 into carbon monoxide and water. According to Surrey University, this reaction can be used to make sustainable ‘synthesis gas’ which is a mixture of CO and H2 that can be converted to numerous chemicals using existing techniques used by the chemicals industry.

DRM involves the conversion of methane and CO2 into ‘synthesis gas’, taking advantage of underutilised hydrocarbon resources such as biogas and offering opportunities for decarbonisation and CO2 recycling in the absence of green hydrogen.

By using a technique called operando-DRIFTS-MS, the team were able to observe interactions of molecules with the surface of these unique dual-function materials while CO2 was being captured and while it was further converted to products via these three reactions. This allowed researchers to determine what makes a DFM work, greatly advancing their ability to design high-performance materials.

"Capturing and using carbon dioxide is key to reach the ultimate goal of net zero by 2050,” said Dr Duyar. “We now have a clearer understanding of how switchable DFMs are able to perform a multitude of reactions directly from captured CO2 which will help us improve the performance of these materials even more via rational design."