Enhancement of Photo-to-Current Efficiency over Two-Dimensional Bi[sub 2]MoO[sub 6] Nanoplate Thin-Film Photoelectrode

Yu, Jianqiang; Zhang, Yan; Gao, Xinglong; Kudo, Akihiko; Xin, Zhao

doi:10.1149/1.2968955

Cited by 11 publications

(6 citation statements)

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“…The band gaps of γ(L)- and γ(H)-Bi 2 MoO 6 are estimated to be 2.7 and 3.0 eV, respectively (Figure c(iv). On the whole, the optical band gap values measured from the Bi 2 MoO 6 thin films are in good agreement with literature reported values for both γ(L)- and γ(H)-Bi 2 MoO 6 . ,− …”

Section: Results and Discussionsupporting

confidence: 90%

“…Among them, the Aurivillius-phase γ-Bi 2 MoO 6 constitutes two distinct structures: (i) a low-temperature-phase, layered γ(L)-Bi 2 MoO 6 and (ii) a fluorite-like, high-temperature-phase γ(H)-Bi 2 MoO 6 , which is formed at elevated temperatures. , The crystal structure of γ(L)-Bi 2 MoO 6 consists of layers of corner-sharing MoO 6 octahedra sandwiched between alternating Bi 2 O 2 layers, whereas γ(H)-Bi 2 MoO 6 has a fluorite-related derivative-type framework with each bismuth atom having eight oxygen neighbors and the molybdenum atom surrounded tetrahedrally by four oxygen neighbors, as illustrated in Scheme . The γ(L)-Bi 2 MoO 6 , with corner-shared MoO 6 octahedra, possesses a relatively narrower optical band gap of 2.7 eV, whereas γ(H)-Bi 2 MoO 6 with MoO 4 tetrahedron coordination exhibits a wider optical band gap of 3.0 eV. ,− Kudo and co-workers found γ(L)-Bi 2 MoO 6 to be an active photocatalyst for O 2 evolution from water containing a Fe 3+ /Fe 2+ redox couple or AgNO 3 under visible light irradiation. − However, γ(H)-Bi 2 MoO 6 was an inactive photocatalyst for O 2 evolution under both visible and UV light . Using density functional theorem (DFT), Kudo and co-workers found the visible light response of γ(L)-Bi 2 MoO 6 to be attributable to a charge transition between the O 2p and Mo 4d orbitals within the corner-sharing MoO 6 octahedra.…”

Section: Introductionmentioning

confidence: 99%

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Concentration-Mediated Band Gap Reduction of Bi₂MoO₆ Photoanodes Prepared by Bi³⁺ Cation Insertions into Anodized MoO₃ Thin Films: Structural, Optical, and Photoelectrochemical Properties

Lou

Amal

Scott

et al. 2018

ACS Appl. Energy Mater.

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A secondary cation insertion technique to fabricate ternary Bi 2 MoO 6 thin films with reduced optical band gaps and shallow valence bands by the controllable insertion of Bi 3+ cations into anodized MoO 3 thin films has been established. Near-complete conversion of the MoO 3 thin film to a low-temperature-phase γ(L)-Bi 2 MoO 6 thin film was achieved when the MoO 3 thin films were subject to hydrothermal treatment in a low Bi(NO 3 ) 3 •5H 2 O solution concentration. In contrast, a bilayered Bi 2 MoO 6 /MoO 3 thin film photoelectrode comprising predominantly a high-temperaturephase γ(H)-Bi 2 MoO 6 oxide−electrolyte interface top region and a MoO 3 oxide−collector interface bottom region was formed when a high Bi(NO 3 ) 3 •5H 2 O solution concentration was utilized. UV−vis spectroscopy shows both the γ(L)-Bi 2 MoO 6 (E g = 2.7 eV) and γ(H)-Bi 2 MoO 6 (E g = 3.05 eV) thin films exhibit smaller band gaps than MoO 3 (E g = 3.4 eV). For γ(L)-Bi 2 MoO 6 , the reduction in optical band gap was attributed to the formation of a higher-lying O 2p valence band maximum while, for the γ(H)-Bi 2 MoO 6 thin film, hybridization of the Bi 6s orbitals with the O 2p valence orbitals lowers the potential of the valence band maximum, leading to the reduced band gap. Overall, the Bi 2 MoO 6 thin films with the highest γ(L)-Bi 2 MoO 6 concentration exhibited the highest photocurrent density. The photocurrent enhancement can be attributed to two main reasons: first, the trilayer Bi 2 MoO 6 /MoO 3 heterostructure obtained from the direct thin film assembly enables a smooth percolation of photoexcited charges from the surface generation sites to the charge collection sites at the Mo substrate, minimizing charge recombination losses; second, the MoO 6 octahedra-coordinated γ(L)-Bi 2 MoO 6 possesses a wide conduction band enabling fast separation and migration of delocalized charges. The secondary cation insertion technique has potential as a universal method to prepare complex oxides with narrow band gaps and shallow valence bands from insertion-type oxides for solar energy applications.

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Section: Results and Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Concentration-Mediated Band Gap Reduction of Bi₂MoO₆ Photoanodes Prepared by Bi³⁺ Cation Insertions into Anodized MoO₃ Thin Films: Structural, Optical, and Photoelectrochemical Properties

Lou

Amal

Scott

et al. 2018

ACS Appl. Energy Mater.

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“…While binary oxides such as TiO 2 , Fe 2 O 3 , WO 3 , etc. have long been studied as water oxidation photoanodes, ,− ternary and quaternary oxides have attracted emerging interest recently because of their diversity and tunability. − …”

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confidence: 99%

Elucidation of CuWO₄ Surface States During Photoelectrochemical Water Oxidation

Gao

Hamann

2017

J. Phys. Chem. Lett.

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Electrochemical, photoelectrochemical, and impedance spectroscopy measurements were performed to investigate the role of CuWO surface states during water oxidation. We found that a capacitive feature related to a surface state is clearly observable under water oxidation conditions. The magnitude of the surface state capacitance is light intensity-dependent, with a peak potential that coincides with the water oxidation onset potential region. The surface state is not observed in the dark nor in contact with nonaqueous solvents. These results strongly support our assignment of this surface state as the buildup of water oxidation intermediate species at the surface of CuWO photoanodes, not a permanent or intrinsic state as previously reported. We suggest this is a general feature that controls the behavior and efficiency of solar water splitting reactions.

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“…The test electrodes were prepared according to a previous study. 14 EIS measurements were carried out in a 0.5 M Na 2 SO 4 solution using a three-electrode system, with a platinum foil electrode as the counter electrode and a Ag/AgCl electrode as the reference electrode. The spectra were recorded with an AC voltage amplitude of 5 mV, with a frequency range of 1 MHz to 10 mHz at 0.5 V.…”

mentioning

confidence: 99%

Enhanced photocatalytic water disinfection properties of Bi2MoO6–RGO nanocomposites under visible light irradiation

et al. 2013

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Bi2MoO6-RGO composite nanoplates with good uniformity and highly oriented growth of the active lattice were successfully synthesized by a simple hydrothermal process with the assistance of graphene oxide. Reduced graphene oxide was observed to be formed on the surface of the Bi2MoO6 nanoplates after the hydrothermal treatment. A remarkable enhancement in the visible-light-driven (VLD) photocatalytic destruction of bacteria was observed over the Bi2MoO6-RGO composite when compared to pure Bi2MoO6.

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Enhancement of Photo-to-Current Efficiency over Two-Dimensional Bi[sub 2]MoO[sub 6] Nanoplate Thin-Film Photoelectrode

Cited by 11 publications

References 25 publications

Concentration-Mediated Band Gap Reduction of Bi₂MoO₆ Photoanodes Prepared by Bi³⁺ Cation Insertions into Anodized MoO₃ Thin Films: Structural, Optical, and Photoelectrochemical Properties

Concentration-Mediated Band Gap Reduction of Bi₂MoO₆ Photoanodes Prepared by Bi³⁺ Cation Insertions into Anodized MoO₃ Thin Films: Structural, Optical, and Photoelectrochemical Properties

Elucidation of CuWO₄ Surface States During Photoelectrochemical Water Oxidation

Enhanced photocatalytic water disinfection properties of Bi2MoO6–RGO nanocomposites under visible light irradiation

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Enhancement of Photo-to-Current Efficiency over Two-Dimensional Bi[sub 2]MoO[sub 6] Nanoplate Thin-Film Photoelectrode

Cited by 11 publications

References 25 publications

Concentration-Mediated Band Gap Reduction of Bi2MoO6 Photoanodes Prepared by Bi3+ Cation Insertions into Anodized MoO3 Thin Films: Structural, Optical, and Photoelectrochemical Properties

Concentration-Mediated Band Gap Reduction of Bi2MoO6 Photoanodes Prepared by Bi3+ Cation Insertions into Anodized MoO3 Thin Films: Structural, Optical, and Photoelectrochemical Properties

Elucidation of CuWO4 Surface States During Photoelectrochemical Water Oxidation

Enhanced photocatalytic water disinfection properties of Bi2MoO6–RGO nanocomposites under visible light irradiation

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Concentration-Mediated Band Gap Reduction of Bi₂MoO₆ Photoanodes Prepared by Bi³⁺ Cation Insertions into Anodized MoO₃ Thin Films: Structural, Optical, and Photoelectrochemical Properties

Concentration-Mediated Band Gap Reduction of Bi₂MoO₆ Photoanodes Prepared by Bi³⁺ Cation Insertions into Anodized MoO₃ Thin Films: Structural, Optical, and Photoelectrochemical Properties

Elucidation of CuWO₄ Surface States During Photoelectrochemical Water Oxidation