Researchers at Sweden’s Lund University have developed an innovative vehicle fuel system that minimizes greenhouse gas emissions and operates in a circular manner. The system utilizes a unique liquid that, when combined with a solid catalyst, turns into hydrogen fuel for cars. After use, the used fluid is removed from the vehicle’s tank and refilled with hydrogen, making it available for reuse. This process forms a closed-loop system that significantly reduces environmental impact.

In two research papers, Lund researchers have demonstrated that the method works, and although it is still basic research, it has the potential to become an efficient energy storage system in the future.

“Our catalyst is one of the most efficient, at least according to published studies,” says one of the authors, Ola Wendt, professor in the Department of Chemistry at Lund University.

Addressing climate impacts and exploring hydrogen gas

Reducing our climate impact requires finding alternative ways to produce, store, and convert energy to reduce carbon emissions from fossil fuels. One method involves the hot topic of hydrogen gas, which many see as the future solution for energy storage. Nature stores energy through chemical bonds, and hydrogen contains the highest energy density relative to its weight.

“But gas can be difficult to handle, so we are looking at hydrogen-filled liquid fuels that can be delivered at the pump, in much the same way as is done at gas stations today.” Ola Wendt he says.

This concept is known as LOHC (Liquid Organic Hydrogen Carrier) and is not new in itself. The challenge is to find the most efficient catalyst possible to extract hydrogen from the liquid.

The system is designed to operate using a liquid “filled” with hydrogen. The liquid is pumped through a solid catalyst to extract the hydrogen. This can be used in fuel cells that convert chemical fuels into electricity, and the “spent” liquid is taken to a separate tank. Only water is expelled.

Refueling and large-scale production

Used fluid can be emptied at a filling station before being refilled with new fill fluid. This would likely mean large-scale production of materials comparable to today’s oil refineries.

“We converted more than 99 percent of the hydrogen gas present in the liquid,” says Ola Wendt.

Researchers are also calculating whether the fuel could be used in larger vehicles such as buses, trucks and airplanes.

“With the larger tanks they have, they might be able to cover about the same distance as a diesel tank. They would also convert about 50% more energy than compressed hydrogen,” says Ola. Wendt says.

Components and challenges

The liquids used are isopropanol (a common ingredient in screen wash) and 4-methylpiperidine.

Does this seem a little too good to be true? Yes, many challenges remain, at least for now. One is that catalysts have a fairly limited lifetime. Another reason is that iridium, which is the basis of the catalyst, is a precious metal.

“However, we estimate that each car requires about 2 grams of iridium. ,” says Ola Wendt.

This is a technical solution based on basic research. Ola Wendt believes that if the decision is made to develop a finished product, the concept could be completed within 10 years if it is economically viable and there is interest from society. I am.

Another issue is how hydrogen is produced. Today, most manufacturing is not climate friendly. Next, hydrogen needs to be stored and transported in an effective way, which is not so easy today. Compressed hydrogen refueling also has risks. Lund researchers hope to solve this problem in their own way.

“Ninety-eight percent of all hydrogen today is fossil-based, produced from natural gas. The byproduct is carbon dioxide. From an environmental perspective, the concept of producing hydrogen for steel, batteries, and fuels is “It makes no sense if it’s done using natural gas,” says Ola Wendt, but explains that a lot of research is being done on how to “produce hydrogen in an environmentally friendly way.” To do. “Hydrogen” can be produced by splitting water into hydrogen and oxygen with the help of renewable energy.

At the same time, Ola Wendt believes that political decisions are needed for renewable and climate-friendly alternatives to gain a proper foothold.

“It needs to be cheaper, and that will require a political decision. Renewable energy has the potential to compete with just digging it out of the ground, where transportation is almost the only cost, as is the case with fossil fuels. There is no gender,” he concludes.

Reference: “Acceptorless dehydrogenation of 4-methylpiperidine over supported pincer-bound iridium catalysts in continuous flow” Kaushik Chakrabarti, Alice Spangenberg, Vasudevan Subramaniyan, Andreas Hederstedt, Omar Y. Abdelaziz, Alexey V. Polukeev, Reine Wallenberg , by Christian P. Hulteberg and Ola F. Wendt, July 27, 2023. Catalyst science and technology.
DOI: 10.1039/D3CY00881A

“Iridium-catalyzed dehydrogenation in a continuous flow reactor for practical on-board hydrogen production from liquid organic hydrogen carriers”, Alexey V. Polukeev, Reine Wallenberg, Jens Uhlig, Christian P. Hulteberg, Ola F. Wendt, March 9, 2022 chemsus chem.
DOI: 10.1002/cssc.202200085