The introduction of the NiFe₂O₄ layer into the hematite results in a reduction in the onset potential, signifying an enhancement in the performance of PEC water splitting. This shift is attributed to the inhibition of electron back transfer from the FTO substrate to the hematite film.

Abstract

We found a new blocking layer (nickel ferrite, NiFe₂O₄), that could be utilized for the suppression of the back recombination, occurring in the hematite (α-Fe₂O₃) photoanode. The photoanode in which the NiFe₂O₄ layer was introduced showed a cathodic shift of the onset potential in the current density versus applied voltage curve. We successfully demonstrated that the NiFe₂O₄ layer effectively inhibited the back recombination in the hematite film through the use of electrochemical and time-resolved spectroscopic methods.