99% of carbon dioxide can be captured with new fuel cell technology

US engineers have tried and tested a new approach to removing CO2 from the atmosphere, which could be a major help in tackling the climate crisis.

A potentially significant leap forward, a team at the University of Delaware, led by Professor Yushan Yan, Henry Belin du Pont Chair of Chemical and Biomolecular Engineering, made the breakthrough after 15 years attempting to improve hydrogen exchange membrane fuel cells, or HEMs. 

These economical and environmentally friendly alternatives to traditional acid-based cells offer plenty of promise for greener travel and transport. However, they are highly sensitive to carbon dioxide levels in the air, with the gas making it difficult for the cells to ‘breathe’. That process reduces performance and efficiency by up to 20%, leaving HEMs roughly on a par with gasoline-based engines in terms of environmental impact.

This is due to how HEM technology works, essentially converting fuel chemical energy directly into electricity. But in doing so, the cells actually capture carbon dioxide from the atmosphere in a process described as ‘self-purging’. This renders the technology redundant for fuel, but potentially incredibly useful for removing C02 from the air. 

‘Once we dug into the mechanism, we realised the fuel cells were capturing just about every bit of carbon dioxide that came into them, and they were really good at separating it to the other side,’ said Brian Setzler, Assistant Professor for Research in Chemical and Biomolecular Engineering and paper co-author.

‘It turns out our approach is very effective. We can capture 99% of the carbon dioxide out of the air in one pass if we have the right design and right configuration,’ added Yan. 

The team’s approach centred on embedding the power source inside the separation membrane by internally short-circuiting the device. By doing this, they found that a cell measuring two inches by two inches could continuously remove 99% of CO2 from the air at a rate of two litres per minute. If scaled for automotive applications, this would mean the equipment would need to be around the size of a gallon carton of milk. 

In related news, the UK’s House of Commons Transport Select Committee has recommended that road charging should reduce road tax in a bid to cut traffic congestion and emissions. The news has come as the controversial Greater Manchester Clean Air Zone, due to be launched in May, has been delayed due to concerns over its affordability and impact on the city-region’s economy. 

Image credit: Matthias Heyde