Fe2TiO5-based photoanodes application in expanded photoelectrochemistry derived from the construction of heterojunction with the co-catalyst role

Abstract

The Fe2TiO5 photoelectrode is limited in photoelectrochemical field (PEC) due to the slow charge transfer kinetics, short carrier diffusion distances and low separation efficiency. Hence, the Fe2TiO5/NiCo-LDH photoelectrodes with dual roles of co-catalyst and heterojunction are constructed, in which the photogenerated carriers are effectively separated and the conductivity is enhanced. At the same time, the surface state of the Fe2TiO5-based photoanode is modulated by the co-catalyst, which drives charge transfer into the electrolyte. With the synergistic effect of inhibiting photogenerated carrier complexation and accelerating charge transfer, the OER photocurrent density of Fe2TiO5/NiCo-LDH photoelectrode is enhanced to 2.42 mA/cm2, which is 3.4 folds higher than that of pristine Fe2TiO5. Specifically, Fe2TiO5/NiCo-LDH photoanode exhibits good stability and photoelectrochemical performance in hydrogen sulfide oxidation reaction (SOR). Similar to the OER, the sulphur oxidation photocurrent density of Fe2TiO5/NiCo-LDH photoelectrodes is enhanced to 0.21 mA/cm2, which is 2 folds higher than that of pristine Fe2TiO5. This work provides a new idea for the modification of Fe2TiO5 photoanodes and also explores a pioneering demonstration for the photoelectrochemical decomposition of hydrogen sulfide.