An international team of researchers has produced green hydrogen by splitting seawater without any pre-treatment, according to a press release by The University of Adelaide on Wednesday, Feb. 1.
The team was spearheaded by Professor Shizhang Qiao and Associate Professor Yao Zheng from the School of Chemical Engineering at the University of Adelaide.
APTOS, CALIFORNIA - JANUARY 10: Gulls fly above breaking Pacific Ocean waves on January 10, 2022 in Aptos, California.
Novel System
It is worth noting that only 1% of the water on Earth is rendered accessible freshwater, but there is an almost endless quantity of seawater that can be utilized.
New estimates also indicate that the quantity of water required to support future hydrogen consumption is significantly less than the trillions of liters of water currently used to extract and burn fossil fuels.
ScienceAlert notes that unwanted chlorine ions in saltwater corrode the catalyst components intended to drive the hydrogen-producing, water-splitting reaction when they are added to an electrolyzer. Massive insoluble precipitates can also develop, preventing large-scale production by obstructing reaction sites.
However, the team's novel system provides a solution to these problems.
"We have split natural seawater into oxygen and hydrogen with nearly 100 percent efficiency, to produce green hydrogen by electrolysis, using a non-precious and cheap catalyst in a commercial electrolyzer," Professor Qiao said in a statement.
Associate Professor Zheng said they used seawater as a feedstock without undergoing a treatment process such as purification, alkalization, and reverse osmosis desolation.
The professor also claimed that the performance of a commercial electrolyzer with its catalysts in seawater is similar to platinum or iridium catalysts being funneled in a feedstock of highly purified deionized water.
Electrolyzers are currently run with highly purified water electrolytes.
Nearly Limitless Supply
According to Associate Professor Zheng, a growing need for hydrogen to partially or entirely replace fossil fuel-produced energy will dramatically worsen the scarcity of freshwater resources.
Seawater is regarded as a natural feedstock electrolyte and is a nearly limitless supply. The team said that this would be more practical for areas with extensive coasts and an abundance of sunlight. But it is not ideal for regions with limited access to seawater.
In comparison to pure water electrolysis, seawater electrolysis is still in its infancy due to corrosion caused by employing seawater and electrode side reactions.
"It is always necessary to treat impure water to a level of water purity for conventional electrolyzers including desalination and deionization, which increases the operation and maintenance cost of the processes," Associate Professor Zheng said.
The work offers a method for using seawater directly without the need for pre-treatment systems or alkali addition. The team claims that it performs similarly to existing metal-based mature pure water electrolyzers.
The system will now be scaled up using a bigger electrolyzer so that it can be employed in industrial operations like ammonia synthesis and hydrogen generation for fuel cells, according to the research team.
The research findings were published in the journal Nature Energy.
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