RMIT Researchers Turn Wastewater Contaminants into Green Hydrogen Catalysts

Researchers from RMIT University, a leading public research institution in Melbourne, Australia, have successfully developed an experimental method to turn wastewater’s high contaminant load into an advantage for producing green hydrogen, potentially reducing reliance on freshwater — a scarce resource in many regions. With more than 80% of global wastewater discharged untreated into the environment, this research offers a new opportunity to turn an environmental liability into a productive asset.

The RMIT team’s approach harnesses specific contaminants in wastewater to accelerate hydrogen production, overcoming the high contaminant loads that typically make wastewater unsuitable for this process.

Their latest work — conducted in collaboration with the University of Melbourne, Australian Synchrotron, and University of New South Wales — builds on previous breakthroughs, including an innovation that rapidly removes microplastics from water using magnets, as well as a technique that boosts hydrogen production using seawater.

Lead researcher Associate Professor Nasir Mahmood, from RMIT’s School of Science, noted that the team found a way to capture platinum, chromium, nickel, and other metals in the water and put these elements to work enhancing green hydrogen production.

“The advantage of our innovation over others to produce green hydrogen is that it harnesses wastewater’s inherent materials rather than requiring purified water or additional steps,” Mahmood said.

Their experimental invention is in the form of electrodes, which are key components for splitting water into hydrogen and oxygen. The electrode has an absorbent carbon surface that attracts metals from wastewater to form catalysts that are stable and efficient at conducting electricity, helping to speed up water splitting.

The materials used to produce this special carbon surface are derived from agricultural waste — a cost-effective element of the innovation that also contributes to the circular economy.

“The catalyst speeds up a chemical reaction without being consumed in the process,” Mahmood said. “The metals interact with other elements in the wastewater to boost the electrochemical reactions needed for splitting water into oxygen and hydrogen.”

As part of the experiments, the team placed wastewater samples in a container with two electrodes — an anode (positive) and a cathode (negative) — and powered the water-splitting process with renewable energy. When electricity flows through the water, it triggers a chemical reaction: at the cathode, water molecules gain electrons to form hydrogen gas; at the anode, water molecules lose electrons to create oxygen.

The result is the separation of water into its basic components, hydrogen and oxygen, which can both be collected and used.

“The produced oxygen can be reintegrated into wastewater treatment plants to enhance their efficiency by reducing organic content,” Mahmood said.

The device enabled continuous water splitting for 18 days in laboratory experiments, with minimal performance decline during that time. The experiments used wastewater that had undergone partial treatment, including the removal of solid waste, organic matter, and nutrients.

RMIT is currently developing a platform of catalytic systems capable of using previously unsuitable water resources, such as wastewater and seawater. This latest proof-of-concept invention is another step forward in that program.

Co-lead researcher Professor Nicky Eshtiaghi, from RMIT’s School of Engineering, said the innovation could potentially reduce the high cost of wastewater treatment while producing a valuable resource — green hydrogen.

“Our innovation addresses both pollution reduction and water scarcity, benefiting the energy and water sectors,” Eshtiaghi said. “By using wastewater, the process helps reduce pollution and makes use of materials considered to be waste.

“We are keen to work with companies globally that are addressing energy and waste as cost and sustainability challenges, as well as water authorities. Collaborations could focus on developing commercial systems to use this technology on a large scale.”

Co-researcher Dr. Muhammad Haris, also from RMIT’s School of Engineering, said further research is needed to refine the catalyst process, making it even more efficient and suitable for commercial use.

“The method needs to be tested with different types of wastewater to ensure it works universally,” Haris said.  

The study, Harnessing wastewater as a catalyst modifier for sustainable hydrogen production, is published in ACS Electrochemistry (DOI: 10.1021/acselectrochem.5c00064).

About RMIT University

Founded in 1887, RMIT University (Royal Melbourne Institute of Technology) is a leading Australian public research institution specializing in technology, design, engineering, and applied sciences. With campuses in Melbourne, Vietnam, and Spain, and partnerships worldwide, RMIT serves more than 90,000 students. The university is recognized for its strong industry collaborations, applied research, and innovation in addressing global challenges such as sustainability, clean energy, and advanced manufacturing. For more information about RMIT University and its ongoing research activities, please click here.

Source/Photo Credit: RMIT University

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