PULLMAN, Wash. – A new, energy-efficient way to produce hydrogen gas from ethanol and water has the potential to make clean hydrogen a more viable alternative to gasoline for powering cars.
Washington State University researchers used the mixture of ethanol and water and a small amount of electricity in a new conversion system to produce pure compressed hydrogen. The innovation means that hydrogen could be made on-site at filling stations, so only the ethanol solution would have to be transported. This is a major step in eliminating the need to transport hydrogen gas at high pressure, which has been a major stumbling block for its use as a clean energy fuel.
“It’s a new way of thinking about how to produce hydrogen gas,” said Su Ha, a professor at the Gene and Linda Voiland School of Chemical Engineering and Bioengineering and corresponding author of the paper published in the journal. , Applied Catalysis A. “If there are enough resources, I think it has a very good chance of having a big impact on the hydrogen economy in the near future.”
Using hydrogen as a fuel for cars is a promising but unrealized clean energy. Like an electric car, a hydrogen fuel cell car does not emit harmful carbon dioxide. Unlike an electric car, it can be filled with hydrogen gas in minutes at hydrogen refueling stations.
Despite the promise of hydrogen technology, storing and transporting high-pressure hydrogen gas in fuel tanks creates significant economic and safety challenges. Due to the challenges, there is little hydrogen gas infrastructure in the United States and market penetration of the technology is very low.
In their work, the WSU researchers created a conversion system with an anode and a cathode. When they put a small amount of electricity into the mixture of ethanol and water with a catalyst, they were able to electrochemically produce pure compressed hydrogen. The carbon dioxide resulting from the reaction is captured in liquid form.
Instead of having to transport dangerous hydrogen gas, the conversion method would mean that existing infrastructure for transporting ethanol could be used and compressed hydrogen gas could be easily and safely created on demand in service stations.
“We already use gasoline containing ethanol at all gas stations,” Ha said. “You can imagine that a mixture of ethanol and water can be easily delivered to a local gas station using our existing infrastructure, and then using our technology you can produce hydrogen ready to be pumped into a hydrogen fuel cell car. We don’t have to worry about storing or transporting hydrogen at all. »
The electrochemical system developed by the team uses less than half the electricity of pure water separation, another method the researchers investigated for producing decarbonized hydrogen. Instead of working hard to compress the hydrogen gas later in the process, the researchers used less energy by compressing the liquid ethanol mixture instead, directly producing already-compressed hydrogen gas.
“The presence of ethanol in water changes the chemistry,” said graduate student Wei-Jyun Wang, co-lead author of the paper. “We can actually do our reaction at a much lower electrical voltage than typically needed for electrolysis of pure water.”
Their system also does not require an expensive membrane unlike other water separation methods. The hydrogen resulting from the electrochemical reaction is then ready for use.
“A process that offers a low-cost electrical energy alternative to water electrolysis and that can efficiently capture carbon dioxide while producing compressed hydrogen could have a significant impact on the hydrogen economy. “said Jamie Kee, postdoctoral researcher at the Voiland School and one of the lead authors. On paper. “It’s really exciting because there are a lot of aspects that play into improving hydrogen production methods.”
Researchers are working to develop the technology and exploit it on an ongoing basis. They are also working to utilize the carbon dioxide captured in the liquid.
The work was funded by the Gas Technology Institute and the US Department of Energy’s RAPID Manufacturing Institute.