Green hydrogen production from seawater analysis...revolutionary new research
Producing green hydrogen from seawater analysis...revolutionary new research
A team of researchers succeeded in electrolyzing seawater without any prior treatment, to produce “green hydrogen”. The research team was led by Professor Shizhang Qiao atUniversity of Adelaide and Assistant Professor Yao Zheng from the School of Chemical Engineering.
The currently common method for producing green hydrogen is to electrolyze water molecules using an electrolyser, where each water molecule consists of an oxygen atom and two hydrogen atoms, and when water is electrolyzed, hydrogen is produced, in addition to oxygen gas; It is an environmentally friendly method, compared to traditional methods that extract hydrogen from natural gas.
In order for us to be able to call the hydrogen resulting from the previous process green hydrogen, the electricity used in the electrolysis process must be generated from renewable energy sources.
Using seawater without any treatment
Professor Qiao said: “We have been able to decompose natural seawater into its primary elements of oxygen and hydrogen with nearly 100 percent efficiency, and this is to produce hydrogen by electrolysis, using an inexpensive catalyst, and an electrolysis device intended for commercial use.”
It is worth noting that the inexpensive catalyst referred to by Qiao is cobalt oxide carried on its surface by chromium oxide. The team published its important research in the journal “Nature Energy”.
Cheng said: “We used seawater as the main input without the need for any pre-treatment processes, such as reverse osmosis, purification, or alkalization. After the experiment, it became clear that the performance of the electrolysis device with seawater - in light of the use of a cobalt oxide catalyst - gave a performance similar to electrolysis processes, which use catalysts of platinum or iridium, and rely on high-purity, deionized water as the main input.”
Cheng added: “Current commercial electrolyzers are powered by electrolyte from high-purity water, but with increasing demand for hydrogen, to partially or completely replace energy generated from fossil fuels. Relying on the current approach will make already limited freshwater resources increasingly scarce; So we turned to seawater as a sustainable alternative.”
Green hydrogen is a sustainable and less expensive resource
There is no doubt that seawater is an inexhaustible resource of natural electrolytes (an electrolyte is any substance that contains free ions that make it an electrically conductive medium), which makes it more practical and sustainable for green hydrogen production, especially for areas with long coastlines and abundant sunlight, but it will certainly not be a practical option in landlocked areas or far from seawater.
Seawater electrolysis is still at an early stage of research and development, compared to pure water electrolysis; This is because seawater contains many ions of different elements, which causes a number of undesirable side reactions on the cell’s electrode, in addition to the corrosion that will result in the electrolysis cells. Due to the complex composition of seawater.
Traditional electrolysis devices for producing hydrogen from water always require treating impure water to an appropriate level of purity, through processes such as: desalination and deionization, but this increases the cost of operation and maintenance. Therefore, the new research - which relies on the use of seawater without any pre-treatment processes, with the use of an inexpensive catalyst - is considered an important step in the future of this promising industry, especially if we know that the efficiency of seawater electrolysis - in this way - was similar to traditional electrolysis of pure water.
Finally, the research team will work to further increase the capacity of the seawater electrolysis device, so that it can be used on a broader commercial scale, such as generating hydrogen for fuel cells and producing ammonia.
