Unveiling the Synergy of Interfacial Contact and Defects in α‐Fe₂O₃ for Enhanced Photo‐Electrochemical Water Splitting

Abstract

Photo‐electrochemical (PEC) water splitting is a promising method for converting solar energy into clean energy, but the mechanism of improving PEC efficiency through the interfacial contact and defect strategy remains highly controversial. Herein, reduced graphene oxide (rGO) and oxygen vacancies are introduced into α‐Fe2O3 nanorod (NR) arrays using a simple spin‐coating method and acid treatment. The resultant oxygen vacancy–α‐Fe2O3/rGO‐integrated system exhibits a higher photocurrent, four times than the pristine α‐Fe2O3. It is well evidenced that the electronic interface interaction between α‐Fe2O3 and rGO is boosted with the oxygen vacancies, facilitating electron transfer from α‐Fe2O3 to rGO. Moreover, the oxygen vacancies not only create interband states in α‐Fe2O3 that can trap photogenerated holes and thus facilitate charge separation but significantly also strengthen the adsorption of oxidative intermediates and reduce the energy barrier of rate‐determining step during oxygen evolution reaction (OER). This study demonstrates an rGO–oxygen vacancy synergistic interfacial contact and defect modification approach to design semiconducting photocatalysts for high‐efficiency solar energy capture and conversion. The generated principle is expected to be extendable to another material system.

Surface Modifications of a Vertically Grown Nanostructure for Boosting Photoelectrochemical Water-Splitting Performance

“…In the final step, the electrons and holes undergo oxidation and reduction of water, generating hydrogen and oxygen, respectively. Various types of n- and p-type semiconductor photoelectrodes have been explored, which include WO 3 , ZnO, Fe 2 O 3 , BiVO 4 , SrTiO 3 , Ta 3 N 5 , TiO 2 , etc., as n-type photoelectrodes and Cu 2 O, CuInS 2 , CaFe 2 O 4 , etc., as p-type photoelectrodes. A comparison of the PEC activity of recently reported nanostructured materials of the above-mentioned semiconductor is provided in Table .…”

Interfacial Charge Transfer Bridge Prolongs Carrier Recombination Lifetimes of CoFe Metal‐Thiolate Framework/Hematite Photoanode for Water Oxidation

“…In the Fe 2p XPS region of CoFe MTF/Fe 2 O 3 (Figure 2a), the two peaks at binding energies (BEs) of 711.2 and 724.8 eV correspond to the spin-orbit states of Fe 2p 3/2 and Fe 2p 1/2 in Fe 2 O 3 , respectively. [17] The peak at a BE of 709.0 eV can be identified as Fe 3+ , while the one at 718.2 eV is associated with the satellite peak (Sat.). [18] The O 1s XPS spectrum of Fe 2 O 3 (Figure 2b) exhibits two distinct peaks representing lattice oxygen (O─Fe, 529.5 eV) and surface-absorbed hydroxyl groups (─OH, 531.2 eV).…”

Unveiling the Significance of Diverse Valence State Second Dopants on Hf-Doped Fe2O3 Photoanodes for Enhanced Photoelectrochemical Water Splitting

“…It is of the utmost importance to develop green, sustainable, and clean energy resources due to the depletion of nonrenewable fossil fuels and the adverse consequences of fossil fuels on the environment. Photoelectrochemical (PEC) water splitting is widely viewed as a potentially fruitful method for producing clean and carbon-free H 2 in future energy portfolios. − Among various metal oxides that can be used as a photoanode material, hematite (α-Fe 2 O 3 ; HT) has been described as an excellent candidate for PEC water oxidation due to its appropriate bandgap (∼2.0 eV), natural abundance, low cost, and high chemical stability. − The high recombination rate of photogenerated electron–hole pairs in bulk or at the surface of HT is likely responsible for hampering its experimental performance. , To address these issues, ion doping and surface modifications have been proposed to lower the carrier recombination rate and increase the reaction rate. − …”