Researchers at Monash University along with help from scientists from the University of Davis in northern California and the Australian Synchrotron have discovered a method to produce hydrogen from water using manganese and sunlight.
Now, in the past I’ve talked about using a variety of catalysts to split water into hydrogen and oxygen. I’ve talked about using sunlight as a renewable energy source also to help in the process of electrolysis. I’ve even talked about some scientists creating an artificial leaf to split water into hydrogen and oxygen using sunlight.
But, this process is different. According to Monash University, “The manganese in the catalyst cycles between two oxidation states. First, the voltage is applied to oxidize from the manganese-II state to manganese-IV state in birnessite. Then in sunlight, birnessite goes back to the manganese-II State.”
They go onto say, “The reaction has two steps. First, two molecules of water are oxidized to form one molecule of oxygen gas (O2), four positively-charged hydrogen nuclei (protons) and four electrons. Second, the protons and electrons combine to form two molecules of hydrogen gas (H2).”
So, you see that sunlight plays two important roles in this process instead of just one. First, sunlight creates electricity to jumpstart the process. Second, the sunlight itself is used to recycle the birnessite back into manganese where the whole renewable process can be recycled into another loop of hydrogen creation. So far, no degradation of the manganese has been reported during this process.