Researchers at Lund University in Sweden are investigating an automotive fuel that consists of liquid converted to hydrogen by a solid catalyst. The used liquid can then be drained from the tank, filled with hydrogen, and then reused in a circular system free of greenhouse gas emissions.

Lund researchers have shown that this 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 effective catalysts, at least when you look at publicly available research,” says Ola Wendt, professor at Lund University’s Department of Chemistry and one of the authors.

The findings were published in the journal Catalysis Science and Technology.

To reduce the impact on the climate, it is necessary to find alternative ways to produce, store and convert energy to reduce carbon dioxide emissions from fossil fuels. One way involves the much-talked-about hydrogen, which many see as the solution of the future in energy storage. Nature stores energy in chemical bonds, and hydrogen contains the highest energy density per weight.

“But gas can be difficult to process, so we are generally looking at a hydrogen-charged liquid fuel that can be delivered through a pump, similar to what happens at gas stations today,” says Wendt.

The concept is known as LOHC (Liquid Organic Hydrogen Carriers) and is not new in that sense. The challenge is to find the most efficient catalyst that can extract hydrogen from the liquid.

The system is designed to operate with a liquid “charged” with hydrogen. The liquid is pumped through a solid catalyst that extracts hydrogen. This can be used in fuel cells that convert chemical fuel into electricity while transferring the “spent” liquid to another tank. The only emission is water.

The used fluid can then be drained at the gas station before refilling with newly loaded fluid. This would likely mean large-scale production of the substance comparable to modern oil refineries.

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

The researchers also calculated whether the fuel could be used in larger vehicles such as buses, trucks and airplanes.

“With the large tanks they have, you can cover almost the same distance with a tank of diesel. You also convert about 50 percent more energy compared to compressed hydrogen,” explains Wendt.

Liquids used: isopropanol (a common screen cleaning ingredient) and 4-methylpiperidine. Sounds too good to be true? Yes, some problems remain, at least for now. First of all, the service life of the catalyst is quite limited. The other is iridium, where the catalyst is a precious metal.

Wendt warns: “But we estimate you need about two grams of iridium per car. This is comparable to today’s catalytic converters, which contain about three grams of platinum, palladium and rhodium, which are also precious metals.”

This is a technical solution based on fundamental research. If a finished product is to be decided upon, Wendt believes the concept could be ready within a decade, provided it is economically viable and of public interest.

Another problem is how hydrogen is produced; Most of today’s production is not environmentally friendly. Then hydrogen needs to be stored and transported efficiently, which is not that easy today. Refueling with compressed hydrogen also has risks. Researchers from Lund hope to solve this in their own way.

“Ninety-eight percent of today’s hydrogen is fossil from natural gas. A byproduct is carbon dioxide. “From an environmental perspective, the idea of ​​producing hydrogen for steel, batteries and fuel is stupid if it’s made with natural gas,” Wendt says, but what “green” currently means is He also explains that there has been a lot of research on how green it is. Hydrogen can be produced by splitting water into hydrogen and oxygen using renewable energy.

He also believes that political decisions are necessary for renewable energy sources and ecologically clean alternatives to gain a suitable foothold.

“It has to be cheaper, and that requires political decisions. “Renewable energy has no chance of competing with something you dig out of the ground, where transport is pretty much the only cost, like fossil fuels,” he concludes.