Seawater Can Now Efficiently Power Fuel Cells

A new development in renewable energy takes advantage of two abundant resources: sunlight and seawater. Researchers at Osaka University have demonstrated a solar cell that efficiently produces hydrogen peroxide (H₂O₂) to be used to created electricity in fuel cells. H₂O₂ is much easier store and transport at high densities than the hydrogen gas that is typically used in fuel cells.

Despite this advantage, H₂O₂ has not been used because it has been difficult to produce. Some methods require too much energy, and other attempts at using sunlight haven’t been efficient enough. The Osaka team created a photoelectrochemical cell that produced higher concentrations of H₂O₂ in seawater than ever before. When sunlight hits the cell, a photocatalyst absorbs photons and uses the energy to make a chemical reaction (specifically, oxidation-reduction) that transforms water (H₂O) into H₂O₂. The researchers discovered that chlorine in seawater helped enhance the photocatalytic activity and led to the unusually high concentration of H₂O₂.

Their cell has a solar-to-electricity efficiency of 0.28 percent, but the researchers are confident that this can be improved by using different materials. The study is described in a paper, “Seawater usable for production and consumption of hydrogen peroxide as a solar fuel,” which published in Nature Communications in May 2016.

Source: Phys.org