Scientists have discovered a clever way to produce hydrogen directly from salty seawater. If renewable energy powers the process, this could be another step towards a clean energy future.
The new device makes some chemical changes to existing technology, allowing hydrogen to be extracted from raw, unrefined seawater, and could alleviate concerns about using precious water supplies.
“We split natural seawater into oxygen and hydrogen … using precious and inexpensive catalysts in commercial electrolyzers to produce green hydrogen through electrolysis.” I will explain Shizhang Qiao, a chemical engineer at the University of Adelaide, Australia, said:
Traditionally, hydrogen fuel has been made using natural gas, but it can also be made by electrolysis.
Electrolysis is the water-splitting reaction that uses electricity to push hydrogen atoms out of elbow-shaped water molecules, and the electrolytic cell is the device in which it occurs.
Currently, this process can be accomplished using power from fossil fuels or renewable sources, but both systems require fresh water. Finding a way to achieve electrolysis in seawater could make the future of green hydrogen fuel production more sustainable.
Concerns about water scarcity have led researchers to develop alternatives to commercial electrolysers that only work with purified fresh water.
Available freshwater accounts for only 1% of the total water on earth, but there is a virtually unlimited supply of usable seawater.
Concerns about water scarcity are correct, but recent estimates suggest that the amount of water needed to sustain future hydrogen use is Uses trillions of liters of water To extract and burn fossil fuels today.
But scientists are still concerned about the environmental impact. For decades they have tried to develop a device to produce hydrogen from seawater, some hurdles.
When placed in an electrolyzer, the unwanted chloride ions in seawater erode the catalytic material that promotes hydrogen production and water splitting reactions. Large amounts of insoluble precipitates are also formed, blocking reaction sites and preventing large-scale production.
A new system developed by Qiao et al. avoids both of these problems.
As described in their new paper, the researchers layered a hard Lewis acid material on top of a series of common cobalt oxide catalysts to split water molecules. In a series of tests, the modified catalyst resisted chlorine attack and prevented precipitate formation.
“This is a general strategy that can be applied to a variety of catalysts without the need for specially designed catalysts or electrolyser designs.” write Researcher of the published paper.
As promising as it may sound, the decades-long effort to develop seawater electrolyzers should serve as a reminder of the challenges in commercializing this and other technologies.
“Direct seawater electrolysis without purification processes or chemical additives is very attractive and has been studied for about 40 years, but the major challenges of this technology remain both catalyst engineering and device design. ,” said the researcher. Note.
Recent progress is encouraging and this new device one of many promising attempt Produces hydrogen from seawater.
For example, recently Chinese and Australian scientists developed a prototype device It is designed to float on the surface of the ocean and use solar energy to split hydrogen from seawater. Another working prototype takes a completely different approach. collect water from moist air before extracting hydrogen.
Of course, the prototype is far from an industrial-scale method, so it’s a good idea to sanely combine potential systems in your pipeline to see which ones come to fruition.
Qiao and colleagues are working to scale up the system using a larger electrolyser. However, many factors can make a potential technology successful or unsuccessful.
Commercialization of any process boils down to costs of materials, energy input, and large-scale efficiencies. Small gains can make a big difference in the amount of hydrogen produced.
Cobalt, a material used in metal oxide catalysts, also not without problemsLike the precious metals used in batteries and solar panels, they are sustainably mined and Recycle as much as possible.
Qiao and colleagues, who tested the set-up’s durability, believe the improved catalyst will go a long way. Their system can provide similar output to commercial electrolysers under the same low temperature and operating conditions.
However, with other researchers make progress Steadily improving the efficiency of conventional electrolysers is really no one’s game.
This research natural energy.
