Unlike the decrease in cathodic current upon light irradiation observed upon applying -1V, when -0.5V was applied we observed an increase in the cathodic current upon irradiation with a measured photocurrent density of 0.48±0.14 µA/cm 2 (Figure ). Upon switching to the positive +0.5V regime, we observed an increase in the anodic current upon irradiation with a measured photocurrent density of 0.07±0.02 µA/cm 2 (Figure ). As before, upon turning off the irradiation, the current density decreased back to the baseline level (prior to irradiation) in both bias regimes. To explain our results, we will refer to the scheme of the electrochemical cell (Figure ), at the different voltage regimes. In general, the current generated on the WE is influenced by both a direct charge transfer between the electrode to/from a species in solution as well as by mass transport across the diffuse layer, whereas each one of the processes can determine the rate limiting step of the reaction. As shown in the scheme, during the reaction, the reactant diffuses to the electrode, where charge transfer takes place, followed by the diffusion of the product into bulk solution.