| In 2012, global energy consumption was 17.5 TW and is expected to increase 37% by the year 2040. Atmospheric carbon dioxide levels have eclipsed 400 ppm and are expected to increase to 450 ppm by 2040. The current energy distribution, which heavily favors fossil fuels, is unsustainable long term. Solar fuels, generated from the oxidation of water, present a carbon free energy source. We have studied a nickel-oxide thin film electrocatalyst for the oxidation of water by electron paramagnetic resonance spectroscopy. Despite early promising results of two distinct signals, electrochemical and EPR investigations provided no detailed information on the electronic structure of the system. We have verified that the bulk of the materiel is composed of a paramagnetic species with S = 1/2 spin state. In a second effort, the oxidations carried out by the iron containing oxygenases were explored because of the diverse array of transformations they affect. To better understand these enzymes we have studied a model Fe(IV)-oxo compound supported by a trigonal non-heme pyrolide platform by parallel mode EPR. We have confirmed that the Fe(IV) center is in the high spin, S = 2 state, similar to those found in the natural enzymes. This compound presents a new addition to a small set of synthetic Fe(IV)-oxo's that have achieved this high-spin state. |
