Redox potentials, calculations electrolyte

Figure 28.5 Current-potential curves for p-GaP under low- to moderate-intensity illumination a 1 M NaCl (pH = 1) electrolyte is employed. Illumination is from a 200-W high-pressure mercury lamp filtered with neutral density filter. Intensity is relative to the full lamp output. The H2/H+ redox potential is -0.3 V vs. SCE in this cell. Thus, this cell yields approximately 400 mV of open-circuit photovoltage. Note that increased illumination increases both the saturation photocurrent and the onset potential. Although the photocurrent is increased at higher light intensities, a calculation of the quantum yield for electron flow indicates that this parameter decreases with increased light intensity.

FIGURE 2.35 Comparison of the electrochemical potential windows of 10 organic electrolytes determined by CV measurements (Experimental and the sum of calculated redox potentials of the most reactive species in each electrolyte (Theoretical V. The different solvent species are indicated by circles (PC), triangles (GBL), and squares (DMSO). (Reproduced by permission of The Electrochemical Society from Maeshima, H. et al. 2014. Journal of the Electrochemical Society 16LG7-G14.)... 

An outstanding challenge is to identify a set of redox couples that could be used as internal references for a wide range of electrolytes, solvents and working electrode conditions. Calculated redox potentials would then be reported as follows ... 

In order to calculate equilibrium electrode potential, we assume that in the part of the cell where a semiconductor electrode is placed, the electrolyte solution contains a redox couple, the equilibrium between the electrode and solution being established due to the reversible electron exchange reaction... 

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