Role of Excess Bi on the Properties and Performance of BiFeO<sub>3</sub> Thin-Film Photocathodes

Prasad, Nitin P.; Rohnke, Marcus; Verheijen, Marcel A.; Sturm, Jacobus M.; Hofmann, Jan P.; Hensen, Emiel J. M.; Bieberle-Hütter, Anja

doi:10.1021/acsaem.3c01926

Cited by 8 publications

(3 citation statements)

References 76 publications

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“…Similarly, the Fe 2p spectrum reveals the doublet peaks at ∼710 and ∼724 eV corresponding to Fe 2p 3/2 and Fe 2p 1/2 , respectively, indicating the valence state of Fe as +4. Further, Fe 2P spectrum shows the presence of a satellite signal at ∼718 eV, representing the Fe–O bond . The broad O 1s spectrum exhibits two peaks located at ∼529.8 and ∼532 eV, corresponding to lattice oxygen (O L ) and surface oxygen defects (O S ), respectively, (Figure e).…”

Section: Results and Discussionmentioning

confidence: 94%

Dual Active Site Mediated Photocatalytic H₂ Evolution through Water Splitting Using CeO₂/PPy/BFO Double Heterojunction Catalyst

Ghosh,

Pal,

Biswas

et al. 2024

ACS Appl. Energy Mater.

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Photocatalytic water splitting generates hydrogen from water and sunlight, but one bottleneck for widespread usage is the poor performance of semiconductor photocatalysts. Manipulating the surface of a catalytic material by introducing different components can tune phase composition and extend the catalytic activity by delayed charge recombination, superior charge transfer, and enhanced light harvesting. A double heterojunction has been fabricated using CeO 2 nanoparticles directly deposited on polypyrrole (PPy) nanofibers, and then Bi 2 Fe 4 O 9 (BFO) nanosheets were grown on CeO 2 /PPy with a significant improvement in visible light absorption. A high photocurrent density of 5.5 μA cm −2 with more negative Flat band potential (−0.47 V vs Ag/AgCl) has been obtained for CeO 2 /PPy/BFO compared to single heterojunction CeO 2 /PPy (∼1.9 μA cm −2 and −0.42 V vs Ag/AgCl). Lowering of charge transfer resistance (R ct ) values from 612 kΩ to 488 kΩ and 415 kΩ and longer charge carrier lifetimes of 4.8, 5.8, and 7.3 μs for CeO 2 , CeO 2 /PPy, and CeO 2 /PPy/BFO, respectively, imply facile charge carrier separation with enhanced interfacial band bending after construction of double heterojunctions. Remarkably, CeO 2 /PPy and CeO 2 /PPy/BFO demonstrated 32 and 71 times higher H 2 generation, respectively, than pure CeO 2 . Based on the possible band edge positions of semiconductors, a double heterojunction n-n-Z-scheme charge transfer pathway has been proposed. Our demonstration provides a paradigm to improve catalytic performance for water splitting through surface engineering of semiconductor photocatalysts.

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Section: Results and Discussionmentioning

confidence: 94%

Dual Active Site Mediated Photocatalytic H₂ Evolution through Water Splitting Using CeO₂/PPy/BFO Double Heterojunction Catalyst

Ghosh,

Pal,

Biswas

et al. 2024

ACS Appl. Energy Mater.

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“…This includes various oxygen species (Ο À or O 2 2À ), hydroxyl groups (OH À ), and surface oxygen vacancies, which are saturated by hydroxyl groups due to adsorbed and deprotonated water on the oxide surface. [67][68][69][70] The third peak can be attributed to organic O species originated from the CÀ O compound of adventitious carbon. [65] The last peak, located at a higher energy, is associated with O 2 and/or H 2 O molecules adsorbed on the surface.…”

Section: Structure and Composition Of The Electrodesmentioning

confidence: 99%

Photoelectrocatalytic Water Splitting by Conformal Copper‐Oxide on Hematite Nanostructures: Dependence on Surface‐States

Benkó,

Shen,

Németh

et al. 2024

ChemElectroChem

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Understanding the pivotal role of surface co‐catalysts is paramount in the strategic design of forthcoming photoelectrodes. However, the nuanced impacts of co‐catalysts remain elusive, particularly in promoting the water oxidation reaction on hematite, especially in connection to surface states denoted as S1 (higher energy) and S2 (lower energy). For this purpose, we tailored two isomorphous hematite nanoarrays with a thin layer of amorphous copper oxide (CuOx), composed of a blend of Cu(I) and Cu(II) species, via a soft electrodeposition technique. Remarkably, we discovered that in pristine hematite (α‐Fe2O3), the S2 state played a pivotal role in activating the CuOx ad‐layer for water oxidation. At lower external biases (approximately 0.9–1.1 VRHE), CuOx served as charge reservoir in equilibrium with the S2 state. Notably, beyond 1.1 VRHE, where the high‐energy holes of the S1 state became available, CuOx was activated indirectly through the equilibrium with the S2 state, and a pronounced enhancement in photocurrent was observed. Conversely, in the case of Ti‐doped hematite (Ti : α‐Fe2O3) devoid of the S2 state, the presence of CuOx resulted in a decline in charge transfer efficiency. Instead of facilitating water oxidation, CuOx adversely affected the S1 surface sites and reduced the charge carrier density in Ti : α‐Fe2O3.

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“…When it comes to p-type BiFeO 3 , all reported p-type behaviors of BiFeO 3 photocathodes originated from intrinsic doping where Bi or Fe vacancies were created during synthesis either intentionally or unintentionally. 5–7,18,19 To our best knowledge, extrinsic doping ( i.e. , introducing an impurity atom via substitutional doping to create acceptor levels), which may allow the hole concentration to be increased more methodically, has not been attempted to enhance the p-type behavior of BiFeO 3 .…”

Section: Introductionmentioning

confidence: 99%

Atomic doping to enhance the p-type behavior of BiFeO₃ photoelectrodes for solar H₂O₂ production

Seo,

Grieder,

Radmilovic

et al. 2024

J. Mater. Chem. A

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Role of Excess Bi on the Properties and Performance of BiFeO₃ Thin-Film Photocathodes

Cited by 8 publications

References 76 publications

Dual Active Site Mediated Photocatalytic H₂ Evolution through Water Splitting Using CeO₂/PPy/BFO Double Heterojunction Catalyst

Dual Active Site Mediated Photocatalytic H₂ Evolution through Water Splitting Using CeO₂/PPy/BFO Double Heterojunction Catalyst

Photoelectrocatalytic Water Splitting by Conformal Copper‐Oxide on Hematite Nanostructures: Dependence on Surface‐States

Atomic doping to enhance the p-type behavior of BiFeO₃ photoelectrodes for solar H₂O₂ production

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Role of Excess Bi on the Properties and Performance of BiFeO3 Thin-Film Photocathodes

Cited by 8 publications

References 76 publications

Dual Active Site Mediated Photocatalytic H2 Evolution through Water Splitting Using CeO2/PPy/BFO Double Heterojunction Catalyst

Dual Active Site Mediated Photocatalytic H2 Evolution through Water Splitting Using CeO2/PPy/BFO Double Heterojunction Catalyst

Photoelectrocatalytic Water Splitting by Conformal Copper‐Oxide on Hematite Nanostructures: Dependence on Surface‐States

Atomic doping to enhance the p-type behavior of BiFeO3 photoelectrodes for solar H2O2 production

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Role of Excess Bi on the Properties and Performance of BiFeO₃ Thin-Film Photocathodes

Dual Active Site Mediated Photocatalytic H₂ Evolution through Water Splitting Using CeO₂/PPy/BFO Double Heterojunction Catalyst

Dual Active Site Mediated Photocatalytic H₂ Evolution through Water Splitting Using CeO₂/PPy/BFO Double Heterojunction Catalyst

Atomic doping to enhance the p-type behavior of BiFeO₃ photoelectrodes for solar H₂O₂ production