Efficient charge transfer and excellent surface water oxidation kinetics are key factors in determining the photoelectrochemical (PEC) water splitting performance in photoelectrodes. Herein, a bilayer TiO 2 /α-Fe 2 O 3 nanorod (NR) arrays photoanode was prepared with deposited Cu-doped NiO x (Cu : NiO x ) hole transport layer (HTL) and CoÀ Pi oxygen evolution reaction (OER) cocatalyst for PEC water oxidation. The hierarchical TiO 2 / α-Fe 2 O 3 composite obtained by a secondary hydrothermal process exhibited an inapparent bilayer structure by embedding the underlayer TiO 2 NR arrays at the bottom part of the post-grown α-Fe 2 O 3 NR arrays. The underlayer TiO 2 NRs acted as an effective shuttling pathway for transferring photoelectrons generated in the upper hematite light absorber layer. A p-type inter-Cu : NiO x HTL was introduced to form a build-in p-n electric field between Cu : NiO x and α-Fe 2 O 3 NRs, which improved the hole extraction from α-Fe 2 O 3 to CoÀ Pi OER catalyst. As expected, the as-engineered TiO 2 /α-Fe 2 O 3 /Cu : NiO x / CoÀ Pi photoanode displayed an excellent photocurrent density of 2.43 mA cm À 2 at 1.23 V versus the reversible hydrogen electrode (V RHE ), up to 4.05 and 2.23 times greater than those of the bare α-Fe 2 O 3 (0.60 mA cm À 2 ) and TiO 2 /α-Fe 2 O 3 , respectively.The results demonstrate that the bottom-up engineering of electron-hole transport channels and cocatalyst modification is an attractive maneuver to enhance the PEC water oxidation activity in hematite and other photoanodes.
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.