Summary:
UCLA researchers in the Department of Materials Science and Engineering have developed a novel reactor design for bias-free microbial electrolysis system operation, enabling efficient high-rate hydrogen production.
Background:
As demand for clean hydrogen production rises, microbial electrolysis systems (MES) continue to show promise for sustainable hydrogen production. Conventional MES require an external voltage to convert organic waste into hydrogen, reducing system efficiency and off-grid applications. To address these limitations, bias-free MES designs have been explored, which utilize no external voltage by relying on energy released during microbial oxidation. Current bias-free MES are limited by scalability and low hydrogen yield because of locally low anode pH, hindering their practical applications. Moreover, advanced wastewater electrolysis systems rely on energy-intensive processes to drive the reactions, which diminishes their overall efficiency and benefit. To improve system performance and commercial viability of bias-free MES, a new design must be developed that significantly increases hydrogen production while enabling bias-free operation.
Innovation:
Researchers at UCLA have developed a novel MES that utilizes a pH-decoupling design to achieve bias-free operation and enhanced system performance. Its architecture reduces energy requirements and enables bias-free hydrogen production. The microbial electrolysis cells can generate an electrical output of ~0.22 kWh m-3, supporting self-sustaining operation and dual-output functionality. Additionally, the system has a hydrogen production current of ~13-14 mA cm-2 and demonstrates long-term operational stability, maintaining a current density of 10 mA cm-2 for over 1,000 hours. These results highlight the system’s ability to sustain high-rate hydrogen production over extended periods, improving commercial viability. Overall, this bias-free MES combines high-rate hydrogen production, efficiency, and stability, positioning the technology as a compelling solution for next-generation sustainable hydrogen production.
Potential Applications:
● Self-powered hydrogen production
○ Decentralized, off-grid
● Hydrogen fueling stations powered by organic waste
● Integration in municipal/industrial wastewater treatment plants
○ Semiconductor processing plant wastewater treatment
● Food/agricultural waste processing
● Anaerobic digestion enhancement
○ Post-treatment for energy recovery
● Biorefineries/chemical plants
Advantages:
● Bias-free operation
● Dual-output
○ Hydrogen and electrical power output
■ Multiple value streams from energy recovery
● High performance
○ High-rate hydrogen production
○ Stable operation (500+ hours at a high current density)
○ High Faradaic and Coulombic efficiency
● Sustainable
● pH-sensitive
Development-To-Date:
First successful demonstration of the invention completed August 2023.
Related Papers:
Huang, Y., et a. (2025). Biocatalyzed Lactate Oxidation Enables Efficient Bias-Free Hydrogen Production in a Three-Chamber Reactor; https://doi.org/10.1021/jacs.5c10688
Huang, Y., et al. (2024). High power density redox-mediated Shewanella microbial flow fuel cells. Nature Communications. Advance online publication. https://doi.org/10.1038/s41467-024-52498-w
Huang, Y., et al. (2021). Redox targeting of silver nanoparticles for enhanced extracellular electron transfer. Science, 373(6556), 653-656. https://doi.org/10.1126/science.abf3427
Reference:
UCLA Case No. 2025-298
Lead Inventors:
Yu Huang, Xiangfeng Duan