Dual-suppression of bulk and surface charges recombination for hematite photoanode.

• Hydrothermal, electrodepositon and subsequent KOH treatment methods were used to obtain E–Ti–Fe 2 O 3 photoanode. • The photocurrent density of E–Ti–Fe 2 O 3 reached 3.1 mA/cm2 at 1.23 V vs. RHE. • The dual-suppression of bulk and surface charges recombination occurs on the E–Ti–Fe 2 O 3 photoanode. • The photocurrent density of E–Ti–Fe 2 O 3 was further improved by the modification of CoPi (4.1 mA/cm2 at 1.23 V vs. RHE). Surface treatments are considered as one of the most effective strategies to overcome charges recombination of photoanodes. Herein, the E–Ti–Fe 2 O 3 photoanode was prepared by hydrothermal, electrodepositon and subsequent KOH treatment methods on the surface of Ti–Fe 2 O 3 photoanode. The photocurrent density of E–Ti–Fe 2 O 3 reached 3.1 mA/cm2 at 1.23 V versus reversible hydrogen electrode (vs. RHE), which was about 6.5 times than that of Ti–Fe 2 O 3 (0.48 mA/cm2 at 1.23 V vs. RHE). The photocurrent density of E–Ti–Fe 2 O 3 was further improved by the modification of CoPi (4.1 mA/cm2 at 1.23 V vs. RHE). The excellent PEC activity can be attributed to the dual-suppression of bulk and surface charges recombination, which was proved by work function (WF) measurements, transient photovoltage (TPV) measurements and photoelectrochemistry (PEC) tests. This research provided a deep insight into the bulk and surface charge recombination of the photogenerated charges for photoanode. The bulk and surface recombination of photogenerated charge was inhibited for the optimized E–Ti–Fe 2 O 3 photoanode, particularly, the loading of CoPi further improve the surface water oxidation kinetics. [Display omitted] [ABSTRACT FROM AUTHOR]