Researchers from the University of New South Wales (UNSW) have used precise 3D imaging to reveal how trapped bubbles affect the efficacy of electrolysers in green hydrogen production.
UNSW’s research focuses on optimising the design of electrolysers, which split water into hydrogen and oxygen using electricity. When powered by renewable energy, the process produces green hydrogen.
To date, industrial-scale electrolysers have faced a critical bottleneck, with hydrogen bubbles generated during operation accumulating within porous electrodes, blocking active sites and severely limiting mass transport at high current densities.
Lead researcher Professor Peyman Mostaghimi from UNSW’s School of Civil and Environmental Engineering says green hydrogen production through water electrolysis is essential for decarbonising hard-to-abate sectors such as steelmaking and heavy-duty transport.
“We found that the shape and structure of the porous electrode are just as important as the electrochemistry,” Mostaghimi says.
“If the structure is designed properly, you can stop bubbles from clogging the system and make it much more efficient.”
X-ray imaging
UNSW researchers combined X-ray imaging with simulations to examine the porous structures, giving them unprecedented access to observe gas bubble behaviour over time without dismantling the cell.
“When water is split, we find tiny hydrogen and oxygen bubbles get trapped inside the electrode, blocking the reaction sites and slowing the movement of water and ions, effectively starving the catalyst of fresh water,” Mostaghimi says.
“We looked at the architecture of these porous materials and found that a highly ordered, uniform pore structure resulted in minimal gas trapping.
“This tells us that the pore structure is directly linked to gas trapping, which gives manufacturers a pathway to designing more efficient systems.”
Researchers are now extending their work to the techno-economic assessment of integrating green hydrogen production with transport and large-scale storage in underground porous reservoirs.
Write to Aaliyah Rogan at Mining.com.au
Images: Unsplash
