A representation of the teams bipolar membrane system that transforms seawater into hydrogen gas. Credit: Nina Fujikawa/SLAC National Accelerator Laboratory
The mixed drink of elements in seawater, consisting of hydrogen, oxygen, sodium, and others, is necessary for life on Earth. However, this elaborate chemical makeup postures an obstacle when trying to separate hydrogen gas for sustainable energy applications.
Recently, a group of scientists from the Department of Energys SLAC National Accelerator Laboratory, Stanford University, University of Oregon, and Manchester Metropolitan University has found an approach to extract hydrogen from the ocean. They accomplish this by funneling seawater through a double-membrane system and electricity.
Their ingenious design showed successful in producing hydrogen gas without producing big amounts of harmful byproducts. The outcomes of their study, recently published in the journal Joule, could assist advance efforts to produce low-carbon fuels.
” Many water-to-hydrogen systems today attempt to utilize a monolayer or single-layer membrane. Our study brought 2 layers together,” said Adam Nielander, an associate staff researcher with the SUNCAT Center for Interface Science and Catalysis, a SLAC-Stanford joint institute. “These membrane architectures permitted us to manage the method ions in seawater relocated our experiment.”
Hydrogen gas is a low-carbon fuel presently used in lots of ways, such as to run fuel-cell electrical lorries and as a long-duration energy storage alternative– one that is matched to store energy for weeks, months, or longer– for electrical grids.
Lots of efforts to make hydrogen gas start with fresh or desalinated water, however those techniques can be costly and energy extensive. Cleansing water is costly, needs energy, and adds intricacy to gadgets, the researchers said.
To deal with seawater, the team implemented a bipolar, or two-layer, membrane system and tested it using electrolysis, a technique that utilizes electricity to drive ions, or charged components, to run a preferred reaction. They started their design by managing the most hazardous aspect to the seawater system– chloride, stated Joseph Perryman, a SLAC and Stanford postdoctoral researcher.
” There are many reactive species in seawater that can interfere with the water-to-hydrogen reaction, and the salt chloride that makes seawater salty is among the primary perpetrators,” Perryman said. “In particular, chloride that gets to the anode and oxidizes will lower the lifetime of an electrolysis system and can actually become unsafe due to the hazardous nature of the oxidation products that include molecular chlorine and bleach.”
The bipolar membrane in the experiment enables access to the conditions needed to make hydrogen gas and alleviates chloride from getting to the reaction.
” We are basically doubling up on ways to stop this chloride response,” Perryman stated.
A home for hydrogen
The ideal membrane system would perform 3 main functions: separate hydrogen and oxygen gases from seawater; aid move just the helpful hydrogen and hydroxide ions while restricting other seawater ions; and help prevent undesired reactions. Recording all three of these together is difficult, and the groups research study is targeted towards checking out systems that can effectively integrate all three of these needs.
Particularly in their experiment, protons, which were the favorable hydrogen ions, travel through among the membrane layers to a place where they can be gathered and turned into hydrogen gas by connecting with a negatively charged electrode. The 2nd membrane in the system permits just unfavorable ions, such as chloride, to take a trip through.
As an extra backstop, one membrane layer contains negatively charged groups that are repaired to the membrane, which makes it harder for other adversely charged ions, like chloride, to relocate to locations where they should not be, said Daniela Marin, a Stanford graduate trainee in chemical engineering and co-author. The negatively-charged membrane proved to be extremely effective in blocking almost all of the chloride ions in the groups experiments, and their system ran without generating harmful by-products like bleach and chlorine.
Along with creating a seawater-to-hydrogen membrane system, the research study likewise provides a better general understanding of how seawater ions move through membranes, the researchers stated. This knowledge can help scientists design more powerful membranes for other applications too, such as producing oxygen gas.
” There is likewise some interest in utilizing electrolysis to produce oxygen,” Marin stated. “Understanding ion flow and conversion in our bipolar membrane system is crucial for this effort, too. Together with producing hydrogen in our experiment, we likewise demonstrated how to use the bipolar membrane to generate oxygen gas.”
Next, the group prepares to improve their electrodes and membranes by developing them with products that are more plentiful and quickly mined. This design improvement might make the electrolysis system simpler to scale to a size needed to generate hydrogen for energy-intensive activities, like the transportation sector, the group said.
The scientists likewise intend to take their electrolysis cells to SLACs Stanford Synchrotron Radiation Lightsource (SSRL), where they can study the atomic structure of catalysts and membranes utilizing the centers extreme X-rays. -.
” The future is brilliant for green hydrogen technologies,” stated Thomas Jaramillo, teacher at SLAC and Stanford and director of SUNCAT. “The basic insights we are gaining are key to notifying future developments for improved efficiency, toughness, and scalability of this technology.”.
Recommendation: “Hydrogen production with seawater-resilient bipolar membrane electrolyzers” by Daniela H. Marin, Joseph T. Perryman, McKenzie A. Hubert, Grace A. Lindquist, Lihaokun Chen, Ashton M. Aleman, Gaurav A. Kamat, Valerie A. Niemann, Michaela Burke Stevens, Yagya N. Regmi, Shannon W. Boettcher, Adam C. Nielander and Thomas F. Jaramillo, 11 April 2023, Joule.DOI: 10.1016/ j.joule.2023.03.005.
This job is supported by the U.S. Office of Naval Research; the Stanford Doerr School of Sustainability Accelerator; the DOEs Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division through the SUNCAT Center for Interface Science and Catalysis, a SLAC-Stanford joint institute; and the DOEs Energy Efficiency and Renewable Energy Fuel Cell Technologies Office.
” Many water-to-hydrogen systems today attempt to utilize a monolayer or single-layer membrane. “These membrane architectures allowed us to control the way ions in seawater moved in our experiment.”
Many attempts to make hydrogen gas start with desalinated or fresh water, but those approaches can be costly and energy extensive. “Understanding ion circulation and conversion in our bipolar membrane system is crucial for this effort, too. Along with producing hydrogen in our experiment, we likewise revealed how to utilize the bipolar membrane to produce oxygen gas.”
