Electricity from seawater: New method efficiently produces hydrogen peroxide for fuel cells

Scientists have used sunlight to turn seawater (H2O) into hydrogen peroxide (H2O2), which can then be used in fuel cells to generate electricity. It is the first photocatalytic method of H2O2 production that achieves a high enough efficiency so that the H2O2 can be used in a fuel cell.

The researchers, led by Shunichi Fukuzumi at Osaka University, have published a paper on the new method of the photocatalytic production of hydrogen peroxide in a recent issue of Nature Communications.

"The most earth-abundant resource, seawater, is utilized to produce a solar fuel that is H2O2," Fukuzumi told Phys.org.

The biggest advantage of using liquid H2O2 instead of gaseous hydrogen (H2), as most fuel cells today use, is that the liquid form is much easier to store at high densities. Typically, H2 gas must be either highly compressed, or in certain cases, cooled to its liquid state at cryogenic temperatures. In contrast, liquid H2O2 can be stored and transported at high densities much more easily and safely.

The problem is that that, until now, there has been no efficient photocatalytic method of producing liquid H2O2. (There are ways to produce H2O2 that don't use sunlight, but they require so much energy that they are not practical for use in a method whose goal is to produce energy.)

In the new study, the researchers developed a new photoelectrochemical cell, which is basically a solar cell that produces H2O2. When sunlight illuminates the photocatalyst, the photocatalyst absorbs photons and uses the energy to initiate chemical reactions (seawater oxidation and the reduction of O2) in a way that ultimately produces H2O2.


Read more at: [link to phys.org]