ZnO and dye-sensitized ZnO nanosheets as photoanode of photoelectrochemical water splitting.

Photoelectrochemical water splitting utilizes energy harvested from the sun to split water molecules to produce green hydrogen. Typically, nanostructured semiconductor materials are needed as the photoanode and/or photocathode active layer. In this research, ZnO with a nanosheet structure is used as the photoanode. The ZnO photoanode was synthesized by electrodeposition method using a constant current (galvanostatic) mode of 1 mA/cm2 with varied times of 10, 25, 50, 75, and 100 minutes. Attaching dye molecules on the ZnO surface is used to extend the light absorption into the visible spectrum. In this research, the interaction of the D205 dye with the ZnO nanosheet is also studied. Dye-loading time of 1, 10, and 100 minutes were applied on the 50 minutes. electrodeposition ZnO nanosheet. It is found that increasing the electrodeposition time does not necessarily increase the output current produced under illumination. The current increases up to 50 minutes of electrodeposition, and shows a decrease after a prolonged time. It is also found that there is also an optimum time for the dye loading on the output current produced. The 10 minutes dye-loading time shows the largest output current. This shows that the optimation of electrodeposition time and dye loading time is an important factor to obtain a good photoanode for photoelectrochemical water splitting. [ABSTRACT FROM AUTHOR]