Successive performance enhancement on a Ge-Ti codoped α-Fe2O3 with AlOOH modification photoanode for photoelectrochemical water splitting

Abstract

The poor charge separation efficiency is the main limiting factor of the α-Fe2O3 photoanode for photoelectrochemical water splitting. In this study, we have discovered that the incorporation of Ge-Ti codoping and AlOOH modification strategies can greatly enhance the charge separation efficiency of the α-Fe2O3 photoanode. By introducing the Ti element, which possesses high conductivity, and further enhancing the charge transfer through Ge doping, we have achieved a synergistic inhibition of charge recombination in the Ge-Ti codoped α-Fe2O3. Additionally, the introduction of AlOOH through modification has led to an increase in the interface band bending, thereby enhancing charge separation by elevating the Fermi band level. Furthermore, through the secondary growth (shorted as SG) of undoped α-Fe2O3 and the incorporation of a NiFeOx cocatalyst, we have successfully adjusted the surface states and reduced the onset potential. Through the collaborative efforts of Ge-Ti codoping, SG, AlOOH modification, and NiFeOx catalysis, we have sequentially optimized the performance of the α-Fe2O3-based photoanode, resulting in an impressive photocurrent density of 3.46 mA cm−2 at 1.23 VRHE, as well as a low onset potential of 0.65 VRHE.