Dear All, I am trying to figure out in which potential OH radicals produce on the surface of the catalyst. If OH radicals are the intermediate of oxygen evolution reaction, can we say thermodynamically it is possible to have OH radicals, at the potential of 0.598 V vs SHE (0.5 V vs Hg/HgO in the CV)?
The standard reduction potential of OH/OH- couple in aqueous solution is 1.90+-0.01 V (NHE), the pKa of OH radical is 11.9+-0.2. At pH 14, the potential of O-./OH- is 1.77 V
"We know that OH radicals are the intermediate of oxygen evolution reaction."
Who are "we?"
I know that OH radical is NOT an intermediate in water oxidation to O2
I agree with Yurii comments.
E°(OH. + e = OH-) = 1.89 V is given by Schwarz, H. A.; Dodson, R. W., J. Phys. Chem. 1984, 88, 3643. See also J. Phys. Chem. A 2010, 114, 4968.
This value gives a Gibbs energy of OH formation of 25.1 kJ/mol. This value is in agreement with the theoretical calculations of P. Cabral do Couto et al., J. Chem. Phys. 2003, 119(14), 7344.
I also think that OH radical is not an intermediate in water oxidation to O2.
A well studied way to generate OH radicals is to use photocatalysis with nano Anatase TiO2
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