Scientists from the University of Hong Kong have made a groundbreaking discovery in the production of hydrogen. They have developed a new variety of stainless steel called SS-H2, which is not only highly resistant to corrosion but also more efficient than titanium. This advancement could significantly reduce the cost of materials for water electrolyzers, ultimately making the production of hydrogen from renewable sources more affordable. The details of this discovery have been published in the magazine Materials Today.
The team of researchers, led by Professor Mensin Juang from the engineering department of Hong Kong University, has achieved a major milestone with the development of SS-H2. This accomplishment is part of Professor Juang’s broader project “Superstal,” which has previously yielded successes such as the creation of an anti-Covid-19 material in 2021 and the development of super-strength steel and super-elastic stainless steel in 2017 and 2020 respectively.
The new stainless steel, SS-H2, exhibits remarkable resistance to corrosion, making it a promising candidate for the production of green hydrogen from seawater. The productivity of SS-H2 in saltwater electrolyzers is comparable to the current practice of using titanium, either from desalinated seawater or acids, but at a significantly lower cost.
One of the key features of SS-H2 is its “sequential double passivation” mechanism, which prevents corrosion in chloride environments up to an ultra-high potential of 1700 mV. This innovative approach sets SS-H2 apart from traditional stainless steels.
An unexpected finding during the study was the discovery of manganese’s previously unknown role. Manganese, which was previously believed to decrease steel’s resistance to corrosion, actually plays a crucial role in the formation of a protective layer on the steel’s surface. This discovery challenges existing theories in the field of corrosion science.
Currently, water electrolyzers require expensive catalysts with gold or platinum coatings. The utilization of SS-H2 would reduce the cost of these components by approximately 40 times, representing a significant breakthrough for industrial applications.
Professor Juang’s team is actively working towards the industrial implementation of SS-H2. They have already produced several tons of SS-H2-based wires in collaboration with a plant in mainland China. Efforts are now underway to incorporate this more cost-effective material in the production of hydrogen from renewable sources.