A novel electrochemical method for simultaneous measurement of real-time potentials and photocurrent of various photoelectrochemical systems.

Abstract Two-electrode configuration is preferably used in practical application of various photoelectrochemical systems, such as green fuel production and cathodic protection. Photo electrodes are extendedly studied but the effects of the dark electrodes on overall performance of PEC systems are not experimentally figured out. To address this issue, herein, a novel electrochemical method achieving simultaneous measurement of photocurrent and real-time potential of the photo electrode and the dark electrode is proposed. With this method, the actual band positions and band bending of the photo electrode under photocurrent going through can be determined correctly. By investigating photoelectrochemical hydrogen production and cathodic protection with ZnO photo anodes, it is revealed that the amplitude of photocurrent is not solely determined by the number of light generated electrons on the photo electrode but also strongly affected by their consuming rate for electrochemical reactions on the dark electrode. These applications demonstrate the practicality, reliability and universality of the proposed method for comprehensive understanding the reactions of various photoelectrochemical systems and eventually for their better development. Graphical abstract Image 1 Highlights • Simultaneous measurements of photocurrent and potentials of the photo and dark electrodes have been achieved. • Actual band structure of the ZnO electrode under photocurrent flowing through is determined. • Photocurrent is not solely determined by photo electrode but also affected by dark electrode. [ABSTRACT FROM AUTHOR]