A new technique could make it possible to produce hydrogen in a cleaner and more sustainable way.
Researchers have developed a cost-effective and energy-efficient method to produce hydrogen directly from seawater, without the need for desalination.
Considerable impacts on the environment
Hydrogen is often seen as a clean fuel and a response to the challenges of energy transition, especially in the most difficult sectors to decarbonise such as manufacturing, aviation and maritime transport. However, the vast majority of hydrogen used in the world is currently produced from fossil fuels, which causes significant greenhouse gas emissions.
As for green hydrogen, obtained by electrolysis of water, it is commercially unviable, representing only 1% of total production in the world. Its manufacturing processes are first of all expensive, because of the catalysts required for electrolysis and their high energy consumption. They are also based on the use of fresh water, up to nine liters to produce one kilogram of hydrogen, a parameter to consider in the current climatic context.
Seawater: a false good idea?
Faced with this last problem, the use of seawater could be an interesting solution. However, its desalination involves additional energy consumption, as well as a completely different impact on the environment. Nasir Mahmood, researcher at MRIT in Melbourne, explains:
The main barrier to using seawater is chlorine, which can be generated as a by-product. If we were to meet the world’s hydrogen needs without solving this problem first, we would produce 240 million tons of chlorine per year, which is three to four times the world’s needs. There is no point in replacing hydrogen produced by fossil fuels with hydrogen production that could harm our environment in an entirely different way.
A discovery full of promise
A team from RMIT has, however, developed a new type of catalyst, specially designed to work with seawater. If it performs well, it could above all be manufactured at a lower cost. Its operation requires very little energy and it can be used at room temperature, which would make it relatively easy to produce on a large scale.
According to Nasir Mahmood, this technology promises to significantly reduce the cost of seawater electrolysis. Enough to meet the Australian government’s goal of making one kilogram of green hydrogen cost as much as producing one kilogram of hydrogen hydrogen from fossil fuels.
Researchers are already working with manufacturers to perfect certain aspects of this technology. The next step will be the development of a prototype which should confirm whether the concept is applicable on a large scale.
Source : ScienceDaily
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