Decoupling pH Dependence of Flat Band Potential in Aqueous Dye-Sensitized Electrodes
By Yu, Yongze; Click, Kevin A.; Chien, Szu-Chia; Sun, Jiaonan; Curtze, Allison; Lin, Li-Chiang; Wu, Yiying
Published in The Journal of Physical Chemistry C
Abstract
When a semiconductor is in contact with an electrolyte, its flat band potential (EFB) is an important quantity for determining band edge positions in photoelectrochemistry. Oxide semiconductors generally have a EFB shift of ?59 mV in aqueous solutions when the pH is increased by 1 unit as a consequence of surface deprotonation. Many of the most desirable redox reactions, such as the reduction of CO2 to HCOOH, or water to H2, also show the same dependence on pH due to the involvement of protons. Therefore, pH cannot be used to tune the relative energy alignment between the electrode and the electrolytes. Here, we demonstrate via Mott