In a continuous obsession with scientists around the world to generate green energy from renewable has opened a new era. A team of scientists at Japan’s Osaka University is very close in their research of obtaining solar energy from the most abundant resource on the planet Earth – the seawater. After performing a series of unique chemical reactions these scientists were able to convert seawater in H2O2, Hydrogen peroxide with the help of sunlight. One more very solid option to the growing number of alternative energy sources in the world.
It is a common practice in today’s age to use Hydrogen (H2) for storing solar energy in the form of chemical energy; this is required as solar fuel cells are almost non-effective at night. But Hydrogen has its own issues of storage, as it needs to be stored either in compressed form or cooled to the liquid state at cryogenic temperatures. This is where the importance of seawater conversion to H2O2 with the help of sunlight comes in picture. Storage of this compound is much simpler and easier as compared to H2 storage. This new method developed by Japanese scientists was not known earlier and is far efficient, simpler, and economical than the earlier methods. There were methods to produce H2O2 but it required so much energy that it could not be a practical method.
“Utilization of solar energy as a primary energy source has been strongly demanded to reduce emissions of harmful and/or greenhouse gases produced by burning fossil fuels. However, large fluctuation of solar energy depending on the length of the daytime is a serious problem. To utilize solar energy in the night time, solar energy should be stored in the form of chemical energy and used as a fuel to produce electricity” as said by the researcher in their paper. Shunichi Fukuzumi, the team leader further stated that “The most earth-abundant resource, seawater, is utilized to produce a solar fuel that is H2O2, the photocatalytic production of hydrogen peroxide.”
The process involves a new photoelectrochemical cell developed by these scientists produce H2O2. When sunlight illuminates the photocatalyst, it starts absorbing photons, and chemical reactions with the energy are initiated, resulting in H2O2. They conducted a test for 24 hours. It showed the H2O2 concentration in seawater reached about 48mM (millimolar), as compared to 2mM in pure water. Though this method isn’t yet as efficient as other solar power processes, it’s just a beginning.
“We are working on developing a method for the low-cost, large-scale production of H2O2 from seawater,” Fukuzumi said. “This will replace the current high-cost production of H2O2 from H2 (from mainly natural gas) and O2.”