Hong Kong Stainless Steel Lowers Green Hydrogen Costs

A research team at the University of Hong Kong (HKU) announced on May 10, 2026, the development of a novel stainless steel, designated SS-H2, designed to withstand the corrosive conditions of green hydrogen production from seawater. This material utilizes a unique dual-passivation mechanism, enabling it to resist corrosion at electrochemical potentials up to 1700 mV, significantly higher than the approximately 1000 mV limit of conventional stainless steels.

The innovation aims to reduce the cost of structural components in electrolyzers, which currently rely on more expensive materials like titanium.

Professor Mingxin Huang's team engineered SS-H2 to form a secondary manganese-based protective layer over the traditional chromium oxide film. This sequential dual-passivation strategy allows the steel to operate effectively in chloride-rich environments, such as seawater electrolysis, where standard stainless steels would fail due to transpassive corrosion.

The discovery challenges existing corrosion science, as manganese is typically considered detrimental to stainless steel's corrosion resistance.

This development could substantially lower the capital expenditure for green hydrogen infrastructure. The HKU team estimates that replacing costly titanium-based structural materials with SS-H2 could reduce structural material costs by approximately 40 times in a 10-megawatt PEM electrolysis tank system. The research, detailed in Materials Today , represents a six-year effort to understand and apply this counter-intuitive corrosion resistance mechanism, potentially accelerating the commercial viability of seawater-based green hydrogen production.