(ORDO NEWS) — Scientists have found a clever way to produce hydrogen directly from salty sea water. This could be another step towards clean energy in the future if renewables are used in the process.
The new device makes several chemical modifications to existing technologies, allowing hydrogen to be extracted from raw, untreated seawater, which could alleviate concerns about using up precious water supplies.
“We split natural seawater into oxygen and hydrogen… to produce green hydrogen by electrolysis using a non-precious and cheap catalyst in a commercial electrolyzer,” explains the chemical engineer. Shizhang Qiao from the University of Adelaide in Australia.
Traditionally, hydrogen fuel is made using natural gas, but it can also be made using electrolysis.
Electrolysis is the process of splitting water. a reaction that uses electricity to push hydrogen atoms out of elbow-shaped water molecules, and an electrolyzer is the device in which this happens.
Right now, this process can be achieved using electricity from fossil fuels or renewable energy sources. energy sources, but both systems require fresh water.
Finding a way to achieve electrolysis using seawater could make the future of clean hydrogen fuel production much more sustainable.
Researchers have been trying to develop an alternative to commercial electrolyzers that only work with purified fresh water, out of concern for water shortages.
Available fresh water is only 1 percent of the total amount of water on Earth, but there is an almost limitless supply of sea water that can be used.
While concerns about water scarcity are true, recent estimates show that the amount of water needed to support future hydrogen use is much less than the trillions of liters of water used today to extract and burn fossil fuels.
Scientists still remember this. environmental impact, however. For decades, they have been trying to develop devices to produce hydrogen from sea water, but they have constantly encountered a number of obstacles.
When released into the cell, unwanted chloride ions in seawater destroy the catalytic materials used to produce hydrogen, water splitting reaction.
Massive insoluble precipitates also form, blocking reaction sites and preventing large-scale production.
The new system developed by Qiao and his colleagues avoids both of these problems.
As described in their new paper, the researchers applied solid Lewis acid to a range of conventional cobalt oxide catalysts to break down water molecules. In a series of tests, the modified catalysts are resistant to chlorine and prevent precipitation.
“This is a general strategy that can be applied to a variety of catalysts without the need for specially designed catalysts and cell design. “, the researchers write in their published paper.
Although it sounds promising, the multi-year effort to develop seawater electrolyzers should serve as a reminder of the challenges facing commercializing this or any other technology.
“Direct electrolysis of seawater without a purification process and chemical additives is very attractive and has been studied for about 40 years, but the main problems of this technology remain both in the development of catalysts and in the design of devices,” the researchers note.
Recent progress is encouraging as this new device is one of many promising attempts to produce hydrogen from sea water.
For example, scientists in China and Australia have recently developed a prototype device designed to float on the surface of the ocean and extract hydrogen from sea water using solar energy.
Another prototype in development takes a very different approach, collecting water from moist air before extracting hydrogen.
Of course, prototypes are far from industrial scale methods, so it’s good to have a healthy mix of potential systems in development to see which ones work.
Qiao and his colleagues are working on expanding their system with a larger cell. But many factors can make or break a potential technology.
Commercializing any process comes down to cost of materials, energy costs, and efficiency at scale, where small gains can make a big difference in how much hydrogen
Cobalt, the material used in metal oxide catalysts, is also not without problems. Like any other precious metal used in batteries or solar panels, it needs to be mined in a sustainable way and recycled whenever possible.
After testing the reliability of their plants, Qiao and his colleagues believe that their modified catalysts can move forward.
Their system can provide a power output similar to a commercial electrolyzer at the same low temperatures and operating conditions.
But as other researchers push for steady improvements in the efficiency of conventional electrolyzers, this really is a game for everyone.
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