Boosting Photocatalytic Oxygen Evolution: Purposely Constructing Direct Z-Scheme Photoanode by Modulating the Interface Electric Field

Ti-Fe 2 O 3 photoanode has received widespread attention in photoelectrochemical(PEC) water spilling because of its optimized oxidative and reductive capability of composites catalyst. However, its low efficiency could limit its development. Herein, in order to improve the efficiency of PEC water spilling, the all-solid-state direct Z-scheme Ti-ZnFe 2 O 4 /Ti-Fe 2 O 3 (TZFO/Ti-Fe 2 O 3 ) nanorod arrays composited with the ideal energy band structure are synthesized by modulating the Fermi level of TZFO for PEC water splitting. The photophysical methods in this work, including the Kelvin probe measurement and transient photovoltage spectroscopy(TPV) measurement, are applied to explore the migration behavior of electric charges at the enhanced interface electric field. Finally, the Z-scheme charge transfer mechanism of TZFO/Ti-Fe 2 O 3 photoanode is proved successfully. Benefiting from the desirable charge transfer at interface electric field, the TZFO/Ti-Fe 2 O 3 exhibits the outstanding photocatalytic oxygen evolution reaction(OER) performance, and the photocurrent of 60TZFO/Ti-Fe 2 O 3 photoanode reaches 2.16 mA/cm 2 at 1.23 V vs. reversible hydrogen electrode(RHE), which is three times higher than that of pure Ti-Fe 2 O 3 photoanode. This work provides a facile approach of modulating interface electric field to optimize the Z-scheme charge-transfer process.