Hydrogen fuel is the key to a greener future. Produced from an inexpensive and readily available resource — water — it’s also the only byproduct of hydrogen-powered cars. Contrast that with the polluting fumes that gasoline-powered vehicles emit.
Hydrogen is produced from water through a process known as water electrolysis. Water electrolysis splits individual molecules of water (H2O) into two hydrogen atoms and one oxygen atom using an electric current. This is done with a cathode and an anode. The cathode contributes electrons to the water and attracts oxygen, and the anode takes electrons from the water and attracts hydrogen.
This process requires a significant amount of energy — something that has, until now, made it an inefficient and impractical fuel source.
Taking a Cue from Nature
Assistant Professor Galia Maayan of the Schulich Faculty of Chemistry at the Technion – Israel Institute of Technology and her student, Naama Gluz, may have a solution. In an article published in Nature Catalysis, they presented a molecular complex (also called an artificial molecular cluster) that dramatically improves the efficiency of water oxidation.
The process mirrors photosynthesis, a natural process that developed in plants, bacteria, and algae through evolution. Energy from the sun is used to transform water and carbon dioxide into organic material and oxygen.
Manganese is an essential part of photosynthesis. And in the case of water electrolysis, it could be used as a catalyst to split water and produce needed hydrogen. But it still requires a large amount of energy to set into motion, and manganese-based catalysts are often unstable and decompose rapidly during the process.
Mn12DH: An Incredible Molecular Cluster
The molecular complex developed by Prof. Maayan and Gluz addresses those concerns. This cluster, which is actually a complex molecule called Mn12DH, is wrapped in an organic shell that allows the manganese complex to dissolve in water, stabilizing it. This mimics the protein shell found in naturally occurring manganese.
Experiments conducted with this complex demonstrate that it produces a large quantity of electrons (electric current) and a significant amount of oxygen and hydrogen without requiring a large amount of energy. And thanks to the shell, it’s also more stable than other manganese-based catalysts.
Gluz is continuing to study how we could use this manganese complex to meet the energy demands of the future.