Surface Self‐Transforming FeTi‐LDH Overlayer in Fe₂O₃/Fe₂TiO₅ Photoanode for Improved Water Oxidation

Abstract

Integrating hematite nanostructures with efficient layer double hydroxides (LDHs) is highly desirable to improve the photoelectrochemical (PEC) water oxidation performance. Here, an innovative and facile strategy is developed to fabricate the FeTi‐LDH overlayer decorated Fe2O3/Fe2TiO5 photoanode via a surface self‐transformation induced by the co‐treatment of hydrazine and NaOH at room temperature. Electrochemical measurements find that this favorable structure can not only facilitate the charge transfer/separation at the electrode/electrolyte interface but also accelerate the surface water oxidation kinetics. Consequently, the as‐obtained Fe2O3/Fe2TiO5/LDH photoanode exhibits a remarkably increased photocurrent density of 3.54 mA cm−2 at 1.23 V versus reversible hydrogen electrode (RHE) accompanied by an obvious cathodic shift (≈140 mV) in the onset potential. This work opens up a new and effective pathway for the design of high‐performance hematite photoanodes toward efficient PEC water oxidation.

Regulating a Zn/Co bimetallic catalyst in a metal–organic framework and oxyhydroxide for improved photoelectrochemical water oxidation

“…The improvement of stability is a subject worth exploring in detail, and a stable semiconductor heterojunction or a passivation layer can improve stability. 48,49…”

Efficient Acidic Photoelectrochemical Water Splitting Enabled by Ru Single Atoms Anchored on Hematite Photoanodes

“…To investigate the charge transfer processes at the photoanode/electrolyte interface, electrochemical impedance spectroscopy (EIS) measurements were performed in the dark (Figure b). The Nyquist plots displayed characteristic shapes with two semicircles, and the results were fitted using an equivalent circuit model (inset of Figure b and Table S4), where R s represents the series resistance, R trap represents the charge transfer resistance in the bulk of the photoanode, and R ct reflects the charge transfer resistance at the electrode/electrolyte interface. , The fitting results showed that the series resistance remained nearly unchanged, while the decrease in R trap after Ru loading can be attributed to the enhanced conductivity of the photoanode due to the partial doping of Ru into Fe 2 O 3 . Importantly, R ct was significantly reduced from 145.6 Ω for Fe 2 O 3 to 54.3 Ω for Fe 2 O 3 –Ru, indicating that the loading of Ru facilitates the injection of photogenerated carriers into the electrolyte for the water oxidation reaction.…”

“…The Nyquist plots displayed characteristic shapes with two semicircles, and the results were fitted using an equivalent circuit model (inset of Figure 4b and Table S4), where R s represents the series resistance, R trap represents the charge transfer resistance in the bulk of the photoanode, and R ct reflects the charge transfer resistance at the electrode/ electrolyte interface. 41,42 The fitting results showed that the series resistance remained nearly unchanged, while the decrease in R trap after Ru loading can be attributed to the enhanced conductivity of the photoanode due to the partial doping of Ru into Fe Remarkably, after incorporating Ru, the carrier density of Fe 2 O 3 −Ru was found to be nearly ten times higher than that of Fe 2 O 3 , underscoring the significant enhancement in the photoanode's conductivity. To further evaluate the active sites, the electrochemically active surface area was assessed (Figures 4d and S15) by determining the electrochemical double-layer capacitance (C dl ) from cyclic voltammograms (eq S4).…”