The utilization of solar energy on a large scale requires its storage. In natural photosynthesis, energy from sunlight is used to rearrange the bonds of water to O2 and H2-equivalents. The realization of artificial systems that perform similar “water splitting” requires catalysts that produce O2 from water without the need for excessive driving potentials. Here, we report such a catalyst that forms upon the oxidative polarization of an inert indium tin oxide electrode in phosphate-buffered water containing Co2+. A variety of analytical techniques indicates the presence of phosphate in an approximate 1:2 ratio with cobalt in this material. The pH dependence of the catalytic activity also implicates HPO42– as the proton acceptor in the O2-producing reaction. This catalyst not only forms in situ from earth-abundant materials but also operates in neutral water under ambient conditions.
Don’t you just love the title of the paper? I would have titled the paper “Splitting Water for Cheap”. The author is interviewed here. This catalyst can split water into H2 and O2 using the energy from a solar cell. Then, when you need electricity, you recombine them in a fuel cell to make water and electricity. So, a closed loop with the only external input being the solar energy. Solar energy can now be stored almost painlessly.
Wonderful. Now, please stop building coal plants.