New catalyst from the Ames Laboratory of the U.S. Department of Energy and staff easily and efficiently extracts hydrogen from hydrogen storage materials. The process takes place at mild temperatures and under normal atmospheric conditions, without the use of metals and additives. The breakthrough offers a promising new solution that solves the long-standing problem of using hydrogen fuel for transportation and other applications.
Hydrogen fuel is one of the potential solutions in a nationwide effort to reduce dependence on fossil fuels. According to the Ministry of Health, it is improving hydrogen storage is the key to promoting hydrogen fuel cell technology. At Ames Laboratory, scientists Long Qi and Wenyu Huang are investigating the evolution of hydrogen from a class of materials called liquid organic hydrogen carriers, or LOHCs.
One of the ways to store hydrogen is chemical. Chemical storage relies on materials reacting with hydrogen molecules and storing them as hydrogen atoms, for example in LOHC. This type of storage allows you to store large amounts of hydrogen in small volumes at ambient temperature. However, in order for hydrogen to be useful, catalysts are needed to activate LOHC and release hydrogen. This process is called dehydration.
Lee explained that other methods of dehydration currently exist, but they cause some problems. Some methods rely on metal catalysts that include platinum group critical metals. Supplies of these metals are limited and expensive. Other methods require additives to release hydrogen. Supplements cannot be reusable and result in a higher total cost because they need to be added in each cycle.
Developed by Qi and Huang Catalyst requires no metals or additives. “It’s pretty simple,” Lee said. “Basically, just add a metal-free catalyst to the LOHC, and then hydrogen gas just pops up, even at room temperature.”
The catalyst consists of nitrogen and carbon. The key to its effectiveness is the structure of nitrogen. Catalytic activity can take place at room temperature due to the unique closely spaced graphite nitrogen in the form of a nitrogen assembly formed during the carbonization process. Nitrogen assembly catalyzes the cleavage of carbon-hydrogen (C ‒ H) bonds in LOHC and facilitates the desorption of hydrogen molecules. This process makes the catalyst more efficient than other catalysts used.
Lee and Huang explained that based on the Ministry of Health’s goals in vehicle technology, the hydrogen storage capacity should be close to 6.5% by weight. They are optimistic about the future of their research to achieve the goal with molecules that have greater capacity.
“This study will have a positive impact on the goal of reducing carbon emissions,” Juan said, “and we will need to develop more efficient catalytic systems.”
У 2019, the transport industry accounted for 29% of total US carbon emissions. Lee said the ease and efficiency of the process could benefit the transport industry in the future. The benefits come from a combination of using LOHC and a catalyst like this. The combination can extract usable hydrogen from storage facilities at lower costs and in milder conditions than modern technology. Higher hydrogen densities can provide more charge for hydrogen fuel cells, which can provide energy to vehicles over long distances.
Both Qi and Huang stressed that this study is an important step in supporting the national mission to become carbon-neutral by 2050 by providing a simple and effective way to dehydrate LOHC.
This study is further discussed in the article “Metal-free carbocatalyst for non-acceptor dehydration of room temperature N-heterocycles” published in Advances in science.
Reference: “Metal-free carbocatalyst for non-acceptor dehydration of N-heterocycles at room temperature” Haitao Hu, Yongqing No, Yuewen Tao, Wenyu Huang, Long Qi and Durga Renfeng No, January 28, 2022 Advances in science.
DOI: 10.1126 / sciadv.abl9478
Ames Laboratory is the National Laboratory of the U.S. Department of Energy’s Office of Science, administered by Iowa State University. Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaboration to address global challenges.
Ames Laboratory is supported by the U.S. Department of Energy’s Office of Science. The Bureau of Science is the largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing issues of our time.
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