Preparation and photoelectrochemical properties of BiFeO₃/BiOI composites

Abstract

We report the preparation, optical absorption and enhanced photoelectrochemical properties of novel BiOI-decorated BFO thin films heterostructures.

Self-Enhancement of Water Electrolysis by Electrolyte-Poled Ferroelectric Catalyst

“…Such a discrepancy is probably from underestimating the density of states of the conduction band using a lighter theoretical electronic effective mass for BFO (calculation details are listed in the Supporting Information, Figure S9), leading to a smaller gap between the Fermi level and conduction band minimum (CBM). However, these values are still reasonably consistent with those prepared by chemical synthesis methods reported elsewhere. − In addition, the position of E F of the BFO is closer to the conduction band edge. It indicates that the synthesized BFO nanopowder in this work possesses an n-type semiconducting characteristic, supported by the presence of oxygen vacancies from the XPS O 1s spectra.…”

“…Benefiting from the characteristics of spontaneous polarization and semiconducting behavior, ferroelectrics have been widely applied in photocatalytic or photoelectrochemical water splitting, which are other approaches to utilizing solar energy for hydrogen production. Particularly, switchable polarization directions in ferroelectrics greatly influence the band alignment at the electrode/electrolyte interface, dominating the charge transfer process and the relative reactions. , Multiferroic BiFeO 3 (BFO) stands out in numerous ferroelectrics due to its large polarization (∼90 mC cm –2 ) and moderate band gap (∼2–2.7 eV), − which lead to effective separation of visible-light-excited electrons and holes through a strong internal electric field. Moreover, the polarization direction of the BFO can further alter the band bending condition at the electrode/electrolyte interface.…”

Enhancement of Charge Transfer in TiO2/BiOI Heterojunction Using BiFeO3 as Interface Modifier for Photoelectrochemical Conversion

“…The energy level values were referred to literatures. 41,42 The electron-hole pairs are separated under built-in electric-field effect, photo-generated electrons injected from BiOI to BiFeO 3 and TiO 2 , and finally collected by FTO electrode, while holes transfer to the surface of BiOI. First, the E cb of BiOI is less than −0.33 eV, therefore, the photo-generated electron in E cb of BiOI could react with O 2 to form O 2 − radicals to realize pathway (1) and (2).…”

MOF composites derived BiFeO3@Bi5O7I n–n heterojunction for enhanced photocatalytic performance

“…Bismuth oxyiodide (BiOI), a kind of bismuth oxyhalides semiconductor with a suitable band gap has been proved to be one of the most promising photocatalytic materials because of the excellent sunlight-harvesting activities [15,16]. The band gap energy of bismuth iodide oxide with iodine deficiency structure is between BiOI [17] and Bi 2 O 3 [18] (such as Bi 4 O 5 I 2 [19], Bi 7 O 9 I 3 , Bi 5 O 7 I, etc). The reason for this phenomenon is that the valence band of the bismuth iodide material depends on the I 2 P and O 2 P orbitals, while the conduction band depends on the Bi 6 P orbitals [20].…”