New electrochemical method splits water with electricity to produce hydrogen fuel — and cuts energy costs in the process
Scientists adapted a method that can produce double the amount of hydrogen when splitting water molecules with electricity.
A new method of splitting water molecules to produce hydrogen is highly efficient, and could offer a pathway to scalable hydrogen production. (Image credit: Panaya Chittaratlert/Getty Images)
Scientists have developed a new technique that doubles the amount of hydrogen produced when splitting water molecules with electricity. The method works by adding a simple organic molecule and a modified catalyst to the reactor.
The adapted method lowers energy costs by up to 40% and may offer a "promising pathway for efficient and scalable hydrogen production," the researchers said in a new study published Dec. 1 in the Chemical Engineering Journal.
Using electricity to split water into hydrogen and oxygen molecules — a method known as electrolysis — could potentially offer a way to create hydrogen with no direct carbon dioxide emissions.
Toward greener production of hydrogen - YouTube 
This works by connecting two metal plates known as electrodes to a direct current supply and submerging the ends of the plates into water. Applying electricity to the circuit generates hydrogen at the negative electrode (anode) and oxygen at the positive one (cathode).
However, electrolysis of water is currently inefficient, expensive and uses a lot of electricity, which often comes from non-renewable sources. The main inefficiency is from producing oxygen at the anode, Heidarpour explained.
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To overcome this issue, the team behind the new study adapted the standard electrolysis setup to replace the oxygen-forming reaction with one that produces hydrogen by oxidizing an organic molecule.
First, the researchers set up two chambers containing potassium hydroxide (KOH) solutions, which were separated by a thin membrane, and then connected an electrode to either chamber to form a circuit. The team added a chemical called hydroxymethylfurfural (HMF) to the anode chamber, as well as a modified copper catalyst. Heidarpour said that chromium atoms, within the surface of their specifically designed catalyst, help favor hydrogen production by stabilizing the copper atoms in their reactive state.
When the team applied electricity, electrons from the anode oxidized the aldehyde groups in the HMF molecules. This generated hydrogen and a byproduct called HMFCA, which may find use as a chemical feedstock to make bioplastics, Heidarpour said. (Aldehydes have a carbon atom doubly bonded to an oxygen atom and a single bond to a hydrogen atom.)