Enhancing the Photoelectrochemical Water Oxidation Activity of α‐Fe₂O₃ Thin Film Photoanode by Employing rGO as Electron Transfer Mediator and NiFe‐LDH as Cocatalyst

Abstract

The shortcomings of poor charge transfer ability and slow surface water oxidation kinetics in the single component photoanode limit the performances of photocatalytic water splitting. Herein, a α‐Fe2O3/rGO/NiFe‐LDH composite photoanode was designed for enhancing photoelectrochemical (PEC) water oxidation activity. The rGO nanosheets serve as an efficient electron transfer mediator for promoting charge transport and separation. The NiFe‐LDH is well anchored on rGO nanosheets and provides additional active sites for accelerating water oxidation reaction kinetics. By the virtue of synergistic effect between rGO and NiFe‐LDH, the composite photoanode achieves a pronounced photocurrent density of 1.46 mA/cm2 at 1.23 VRHE (V vs. reversible hydrogen electrode), which is 2.86 times of α‐Fe2O3. Moreover, the onset potential exhibits a significant cathodic shift of 230 mV. This work provides a valuable strategy for the design of photoanode with light absorber, rGO electron transfer mediator and other cocatalysts to achieve efficient and stable PEC water splitting.

Low Voltage Deposition of NiCoV Layered Double Hydroxide Nanosheets on BiVO4 Photoanodes for Photoelectrochemical Water Splitting

“…This results in synergistic effects among the metal species. The presence of low-valence V species as electron donors alters the electron cloud density of the connected metals, thus enhancing catalytic performance. − Figure S8 provides XPS images of the bare BiVO 4 . Compared with the BiVO 4/ NiCoV-LDH/-0.1 V sample, there was no change in the electron binding energy of the Bi species.…”

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

“…26 The deposition of MOOH on photoanodes has been proven to be a promising method to enhance the PEC-WS performance. [27][28][29] For example, Bi et al reported the preparation of an ultra-thin FeOOH with oxygen-rich vacancies as an oxygen-releasing catalyst on a nanoporous BiVO 4 photoanode. The ultra-thin FeOOH significantly promoted the hole transport, reduced the surface charge recombination, and increased the number of surface active sites.…”

NiFe-LDH-Decorated Ti-Doped Hematite Photoanode for Enhancing Solar Water-Splitting Efficiency

“…However, the surface reaction is a difficult problem to overcome because the reaction rate of water evolution of oxygen at the anode is five orders of magnitude less than the evolution of hydrogen at the cathode. Therefore, a significant amount of work has utilized catalysts to rationally modify photoanodes for water oxidation. ,, Although Ir- and Ru-based catalysts exhibit high catalytic activity in water oxidation, their expensive cost limits their large-scale application. , Layered double hydroxides have been widely applied in catalysis, adsorption, energy storage, and conversion systems due to cheap cost, adjustable chemical composition, effective catalytic activity to the oxygen evolution reaction, and easy combination with semiconductors. − Xiang et al fabricated CoAl-LDH/BiVO 4 as a photoanode, leading to the onset potential prominently reduced from 0.9 to 0.36 V vs RHE . Shao et al fabricated ZnO@NiCo-LDH, Co 3 O 4 @NiCo-LDH, and TiO 2 @NiCo-LDH core–shell structures and obtained enhanced photocurrent densities .…”