Improving the charge separation efficiency by embedding the electron transfer layer of hematite photoanode for photoelectrochemical water oxidation

The photogenerated hole transfer from the bulk to the surface is highly valued in the rational design of advanced photoanodes. However, the transfer of photogenerated electrons to the FTO (fluorine-doped tin oxide glass) substrate has a vital influence on the separation behaviors of photogenerated charges as well, which would regulate the photoelectrochemical (PEC) performance of photoanodes in turn. Herein, the W-TiO2/Ti-Fe2O3 heterojunction was fabricated for the first time by inserting W-TiO2 as the electron transfer layer between the Ti-Fe2O3 photoanode and the FTO substrate. Benefitting from the unique electron transport channel of W-TiO2, the photogenerated electrons in Ti-Fe2O3 could smoothly migrate to FTO, while photogenerated holes water oxidation kinetics is promoted and then easily participate in water oxidation reaction. As expected, W-TiO2/Ti-Fe2O3 exhibits a remarkable negative onset potential and a slight improved photocurrent density.