Successfully fabricated a filter to remove 99% of CO2 in the air, operating with clean hydrogen

Engineers at the University of Delaware have successfully demonstrated a method to remove 99% of carbon dioxide from the air, through an advanced electrochemical machine that uses energy from hydrogen. Major breakthroughs could lead to more environmentally friendly fuel cell technologies in the future.

The research team, led by Professor Yan Yushan, has published the CO2 collection method in the journal Nature Energy.

An illustration of how a hydrogen-operated CO2 filtration system works.

Technology to give wings to fuel cells

Fuel cells operate by a series of reactions that convert chemical energy into electrical energy. They can become a lifeline for vehicles that use multiple types of energy at the same time, or help reduce vehicle emissions.

Professor Yan has been working with hydrogen exchange membrane (HEM) energy cells for many years, trying to improve it to replace the widely used acid fuel cell. However, the HEM fuel cell has one big minus: it is extremely sensitive to CO2 in the air. Basically, HEM batteries cannot 'breathe' normally when the air is dense with carbon dioxide.

The weakness causes the fuel cell to reduce its performance by up to 20%, making the clean fuel no longer any better than the fuel. For the past 15 years, Professor Yan's research team has sought to overcome the shortcoming of potentially rich technology.

A few years ago, the team noticed the benefit of a disastrous weakness: it could become a carbon dioxide filter solution.

'Once we got to the bottom of the mechanism, we realized that the energy cell absorbs most of the carbon dioxide it interacts with, plus they separate [carbon dioxide] very efficiently,' assistant professor Brian Setzler, co-author of the new study.

The functionality isn't suitable for an energy storage device, but if the team can take full advantage of its ability to filter carbon dioxide on its own, the device could become an efficient CO2 separator.

What if cars were fitted with a CO2 filtration system that was 99% efficient?

'It turned out that this approach worked very well. We can remove 99% of the carbon dioxide in the air in just one filter, if we design the right model and fine-tune the function,' Professor Yan said.

The team found a way to power the electrochemical system by entering the membrane separating the two energy cell components. This method will cause the battery to short internally.

'It's true that there are many risks, but we were able to control the fuel cell short circuit with hydrogen. And by using a pre-shorted separator, we were able to eliminate oversized components, such as dipole plates, current receivers or wires commonly found in fuel cell assemblies." , researcher Shi Lin said.

Hydrogen is still called the clean fuel of the future.

The team of scientists has an electrochemical device that looks like a regular filter used in gas separation, but with the ability to continuously absorb even the smallest amount of carbon dioxide, the device has the potential to huge application capacity.

Research results show that a 5x5cm electrochemical cell can remove up to 99% of carbon dioxide in a continuous flow of air at a speed of 2 liters / minute. In previous experiments, a device the size of a soda can could filter 10 liters of air per minute, removing up to 98% of CO2.

According to assistant professor Setzler, when scaled up to fit into a car, the device will be the size of a 5-liter can. However, its application will not stop there. It will offer lighter, more efficient carbon dioxide filtration technologies for use in enclosed spaces such as submarines or spacewalkers, which require state-of-the-art air filtration systems. Gradually, it will find a place in civil aircraft, high-rise buildings or many other structures.

"We've got some ideas for long-term applications that could really help us get to that future," said scientist Setzler. Professor Yan Yushan founded the company Versogen for the purpose of clean hydrogen fuel research, and will invite Shi Lin to join the team when this researcher successfully defends his doctoral thesis.