  Metal-organic frameworks (MOFs) provide a versatile and tailorable material
platform that embody many desirable attributes for photocatalytic
water-splitting. The approach taken in this study was to use Density Functional
Theory (DFT) to predict the thermodynamic energy barriers of the oxygen
evolution reaction (OER) for three MOF functionalizations. A Zr-MIL-125 MOF
design was selected for this study that incorporates three linker designs, a
1,4-benzenedicarboxylate (BDC), BDC functionalized with an amino group
(BDC+NH2), and BDC functionalized with nitro group (BDC+NO2). The study found
several key differences between homogeneous planar catalyst thermodynamics and
MOF based thermodynamics, the most significant being the non-unique or
heterogeneity of reaction sites. Additionally, the funcationalization of the
MOF was found to significantly influence the hydroperoxyl binding energy, which
proves to be the largest hurdle for both oxide and MOF based catalyst. Both of
these findings provide evidance that many of the limitations precluding planar
homogeneous catalysts can be surpassed with a MOF based catalyst. While none of
the MOF designs selected for this study out-performed state-of-the-art oxide
based catalysts, the BDC+NH2 proved to be the best with a predicted
over-potential for spontaneous OER evolution to be 3.03eV.
