Overcoming hydrogen’s cost barriers by ensuring both sides of the electrolyzer do useful work.
By Dr. Ali Seifitokaldani and Hamed Heidarpour
Green hydrogen has become one of the most frequently discussed solutions in the clean energy transition. The idea is simple and powerful: use renewable electricity to split water into hydrogen and oxygen, then use the hydrogen as a clean fuel or chemical feedstock. At the point of use, hydrogen produces no carbon dioxide, making it attractive for hard-to-decarbonize sectors such as heavy industry, long-distance transportation, and chemical manufacturing.
However, there is a catch. Hydrogen may be clean when it is used, but the way we make it is often not clean at all. Most hydrogen today is still produced from natural gas, a process that releases significant amounts of carbon dioxide. Water electrolysis offers a cleaner route, but it remains expensive and energy-intensive. A major reason is what happens at the anode, the counter electrode of the electrolyzer, where oxygen is produced through the oxygen evolution reaction. This reaction is slow, inefficient, and consumes a large share of the electrical energy required by the overall process.
Enhancing productivity
In the Electrocatalysis Lab at McGill University, a different question is being considered: what if the anode did something more useful than simply produce oxygen?
This question has led the lab toward a new family of electrolysis systems in which the oxygen evolution reaction is replaced by the oxidation of organic molecules. In one recent study published in the Chemical Engineering Journal, the team used hydroxymethylfurfural (HMF) as a model compound. HMF can be obtained from biomass-derived resources, including non-food plant materials and residues from industries such as pulp and paper. Instead of forcing the electrolyzer to produce oxygen at the anode, the lab used HMF oxidation, a reaction that requires less energy and produces a valuable chemical product.
The result is a more productive use of electricity. At the cathode, the electrolyzer still produces hydrogen. At the anode, however, the oxidation of HMF can also generate hydrogen while converting HMF into a value-added product, HMFCA. In other words, both sides of the electrochemical cell are contributing to useful chemistry. This changes the logic of hydrogen production from a single-output energy process into a combined energy-and-chemical process.
One way to think about this approach is that it removes a bottleneck. In conventional water electrolysis, the anode reaction is necessary, but not especially valuable: oxygen is produced, but the process is slow and energetically demanding. By replacing that reaction with the oxidation of aldehydes or biomass-derived molecules, the electrolyzer can operate at lower voltage. Since electricity is one of the main costs and environmental factors in green hydrogen production, lowering the required voltage could make the process more attractive both economically and environmentally.
A catalyst that lasts
However, turning this idea into a practical technology requires more than a clever reaction. The catalyst must remain active and stable under electrochemical conditions. This has been one of the major challenges in the field. Copper is an attractive catalyst because it is relatively abundant and can promote useful organic oxidation reactions, but under operating conditions it can change surface structure, oxidize, or lose performance over time.
To address this challenge, the lab team developed a chromium-modified copper catalyst. The chromium plays a stabilizing role, helping copper remain in the metallic state that is most useful for the reaction. Using X-ray absorption spectroscopy at the Canadian Light Source, we were able to study the catalyst at the atomic scale and better understand how its structure evolved during operation. These measurements helped explain why the modified catalyst was more stable and more efficient than unmodified copper.
Thinking beyond HMF
The HMF study is an important proof of concept, but it is not the end of the story. HMF is a useful model molecule, and it points toward the broader potential of biomass-assisted electrolysis. At the same time, HMF is not yet produced globally at the scale of major commodity chemicals. For this technology to become practical, the opportunity may not be to buy highly purified HMF and ship it to hydrogen plants. A more realistic pathway is integration with existing industries that already generate organic-rich streams.
This is why our lab is expanding the concept to other aldehydes and related molecules. Many aldehydes can be found in, or produced from, biomass processing, agricultural residues, pulp and paper operations, and emerging biorefinery systems. These streams are often chemically complex, and in many cases, they are treated as low-value byproducts or waste. Electrochemical conversion offers a way to extract more value from them while producing hydrogen at lower energy cost.
The lab is therefore exploring a wider platform: converting aldehydes into organic acids while producing hydrogen at the anode, and pairing that with hydrogen evolution or other valuable reduction reactions at the cathode. This includes work on molecules such as formaldehyde, acetaldehyde, benzaldehyde, and other biomass- or industry-relevant aldehydes. The scientific goal is to understand the reaction mechanisms and design catalysts that can guide these reactions selectively. The practical goal is to build systems that can eventually tolerate real feedstocks, not just clean laboratory solutions.
The road to practical scale
There is still a long way to go. Catalyst stability must be demonstrated over much longer operating times, moving from hours to hundreds or thousands of hours. The systems must be tested with realistic mixtures that contain impurities and changing compositions. Techno-economic and life-cycle analyses are also essential to identify where the approach makes the most sense and where it does not.
This technology is not meant to replace all forms of green hydrogen production. It will be most useful where there’s a local source of suitable organic feedstock and a need for hydrogen or value-added chemicals. But in those settings, it could create a powerful new model: using renewable electricity not only to make clean fuel, but also to upgrade waste-derived molecules into useful products.
By making both electrodes work harder and smarter, biomass-assisted electrolysis could help bring green hydrogen closer to practical, lower-cost, and more sustainable production.
Dr. Ali Seifitokaldani, Hamed Heidarpour
Dr. Ali Seifitokaldani is an Associate Professor in Chemical Engineering at McGill University and Canada Research Chair in Electrocatalysis for Renewable Energy Production and Conversion. His research focuses on designing catalysts and electrochemical systems for green hydrogen production, CO2 conversion, biomass upgrading, and sustainable chemical manufacturing.
Hamed Heidarpour is a PhD candidate in the Department of Chemical Engineering at McGill University. His research focuses on process development for sustainable chemical production from low-grade compounds through electrochemical methods.