Green hydrogen, as an important clean fuel of the future, is produced using renewable energy and is expected to achieve zero emissions. However, the production process typically requires large amounts of pure freshwater, which is costly in water-scarce regions. At the same time, more than 80% of the world's wastewater is discharged into the environment without treatment, causing serious ecological harm. Now, a research team led by RMIT University has found a way to address both problems.
The study, conducted in collaboration with the University of Melbourne, the Australian Synchrotron, and the University of New South Wales, aims to transform global environmental responsibility into productive assets. The team's experimental technology converts the pollutant load in wastewater into catalysts for producing green hydrogen, providing a pathway for sustainable fuel production without the need for freshwater.
The team's breakthrough lies in utilizing existing metals in wastewater, such as platinum, chromium, and nickel, to enhance the hydrogen production process. Instead of filtering out these metals, the system captures and utilizes them. Associate Professor Nasir Mahmood from the School of Science at RMIT University stated that compared with other innovations in green hydrogen production, this approach has the advantage of using inherent substances in wastewater without requiring pure water or additional steps.
The team developed a special electrode with an adsorptive carbon surface that can absorb metals from wastewater. These metals then form stable catalysts that help conduct electricity and accelerate the water-splitting process. Mahmood explained that the metals interact with other elements in the wastewater to promote the electrochemical reactions needed to split water into oxygen and hydrogen. The carbon material used in these electrodes is made from agricultural waste, further increasing the system's sustainability and cost-effectiveness.
In laboratory tests, the researchers placed two electrodes in a container of partially treated wastewater and applied renewable energy. At the cathode, water molecules gain electrons and release hydrogen gas; at the anode, they lose electrons and produce oxygen gas. Mahmood said the generated oxygen can be reintroduced into wastewater treatment plants to improve their efficiency. The system ran continuously for 18 days with minimal performance degradation. The wastewater used had been pre-treated to remove solids, organics, and nutrients, making it representative of real-world applications.
RMIT's innovation is part of a broader catalytic system platform aimed at producing clean hydrogen from difficult-to-treat water sources such as wastewater and seawater. Professor Nicky Eshtiaghi from the School of Engineering at RMIT University noted that this innovation addresses both pollution and water scarcity issues, benefiting the energy and water sectors. By utilizing wastewater, the process helps reduce pollution and makes productive use of materials previously considered waste.
Currently, the team is seeking industry and government partners to scale up the technology. Joint researcher Dr. Mohammad Harris stated that more research is needed to test the method's applicability across different types of wastewater.
