Hydrogen peroxide (H₂O₂) in water has been proposed as a promising solar fuel instead of gaseous hydrogen because of advantages on easy storage and high energy density, being used as a fuel of a one-compartment H₂O₂ fuel cell for producing electricity on demand with emitting only dioxygen (O₂) and water. It is highly desired to utilize the most earth-abundant seawater instead of precious pure water for the practical use of H₂O₂ as a solar fuel. Here we have achieved efficient photocatalytic production of H₂O₂ from the most earth-abundant seawater instead of precious pure water and O₂ in a two-compartment photoelectrochemical cell using WO₂ as a photocatalyst for water oxidation and a cobalt complex supported on a glassy-carbon substrate for the selective two-electron reduction of O₂. The concentration of H₂O₂ produced in seawater reached 48 mM, which was high enough to operate an H₂O₂ fuel cell.

Nature Communications 7, Article number: 11470 doi:10.1038/ncomms11470
Received 02 June 2015 Accepted 30 March 2016 Published 04 May 2016

http://www.nature.com/ncomms/2016/160504/ncomms11470/full/ncomms11470.html