Since the turn of this century, hydrogen and hydrogen-powered fuel cells have been touted as instrumental in the fossil fuel phase-out. However, cost-competitive and sustainable production of large amounts of hydrogen has proven more difficult. An international team of researchers led by Umeå University, Sweden have created a catalyst-based system for electrolysis of water which, if brought to scale, could bring cost efficiency to large-scale water electrolysis systems.
A research team from Finland, Sweden and Vietnam have developed a catalyst-based water electrolysis system that they claim could be used to produce sufficiently large amounts of hydrogen for it to be a cost-competitive energy carrier in the production of renewable diesel or jet fuel.
Carried out under the Bio4Energy research platform, an initiative launched by the Swedish government in 2009, the findings entitled “Robust hierarchical 3D carbon foam electrode for efficient water electrolysis” have recently been published by Springer Nature in its Scientific Reports series.
The system that we have created is robust, scalable and cheap. A further advantage is that we made it work using an alkaline saltwater solution. In principle you could run these systems on sea water, said corresponding author Jyri-Pekka Mikkola, Professor at Bio4Energy lead partner Umeå University.
Melamine and cobalt oxide
What the researchers set out to do was not necessarily to find the most productive catalyst, but rather one that was cheap, environmentally benign and—above all—performed with great stability and had the potential for industrial scale up.
With work having gone on since the start of Bio4Energy’s first programme period, in 2010, they gradually perfected their idea of a catalyst comprising a three-dimensional, lightweight structure based on commercially available and cheap melamine foam and the naturally occurring metal cobalt transformed into cobalt oxide.
As in any form of water splitting, the technology involves passing an electric current through an electrode (the catalyst) to spur a reaction in which the oxygen and hydrogen atoms that make up a water molecule (H2O) separate and bubble off on opposite sides of the electrode.
However, typical process problems tend to be sluggishness of the reaction and lack of stability in the system. Since hydrogen must be made in large quantities at a time for storage to be meaningful, this has meant that many an attempt at hydrogen production for transport fuel making has been discarded as being too complicated and costly.
Hydrogen gas is difficult to store but it is possible if you have a continuous source that produces hydrogen in large amounts and over a sufficiently large surface area. With our system, it can be produced in such amounts. The surface area needs to be large for it to be meaningful, explained Mikkola.
Cost competitive carbon free reducing agent
In their laboratory experiments, the researchers have used pyrolysis to initiate the reaction that the catalyst then speeds up enabling electrolysis to occur. For industrial conditions, the researchers see renewable power sources will provide the electrical impulse needed to drive the reaction.
Simply put this is a system that generates oxygen and hydrogen. Pure oxygen has a lot of energy and can find many uses. Hydrogen is quite a multifaceted resource. You can burn it directly for energy. You could also use it to reduce materials, for instance in the steelmaking of the future. Today you pump hefty amounts of coke into a blast furnace [to transform iron to steel], but this spurs the formation of carbon dioxide. Instead, in principle, you could add hydrogen as a reducing agent. Then there is no [direct] formation of carbon dioxide. However, the hydrogen produced today from fossil gas is too expensive for it to be a viable alternative, ended Mikkola.