The orientation dependence of the photochemical reactivity of BiVO<sub>4</sub>

Munprom, Ratiporn; Salvador, Paul A.; Rohrer, Gregory S.

doi:10.1039/c4ta06045h

Cited by 24 publications

(22 citation statements)

References 40 publications

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“…For the undoped sample, the light source was in contact with the quartz slip, the power was 330 mW (0.75 A and 0.44 V), and the exposure time was 60 s (consistent with our previous studies 21,28 ). Stoichiometric ratios of Bi 2 O 3 , V 2 O 5 , NaCO 3 , and MoO 3 were mixed and then wet ball-milled in ethanol for 24 hours using YSZ as a grinding media.…”

Section: Methodssupporting

confidence: 67%

“…21 Indexing was carried out using a tetragonal unit cell in the Laue group 4/m with a = b = 5.1509 Å and c = 11.73 Å, for both the monoclinic and tetragonal samples. To obtain the relationship between reactivity and orientation, the surface orientations of grains were quantified using electron backscatter diffraction (EBSD) in a Quanta200 SEM (FEI, Hillsboro, Oregon) equipped with an orientation imaging microscopy (OIM) system.…”

Section: Methodsmentioning

confidence: 99%

“…12,13 However, photo-generated electron-hole recombination is reported to limit the performance of BiVO 4 . 4,[21][22][23] In marker reaction experiments, reduction appears favored on (001) surfaces and oxidation appears favored on surfaces away from the (001). 15 Some of these methods have already been used to introduce internal fields in BiVO 4 .…”

Section: Introductionmentioning

confidence: 99%

“…14 Internal fields in photocatalysts are integral to charge separation, arising from surface terminations and ferroelectric phenomena in single-phase materials, and polymorph or p-n junctions in multi-phase samples. [20][21][22][23] While the origin of these observations can be associated with different internal fields at or between different facets, 4,[20][21][22][23] other factors are known to affect the reactivity and it is generally thought that a single simple parameter might not be sufficient to describe the orientation dependence of the reactions. For example, heterojunctions between Co 3 O 4 and BiVO 4 have shown notable improvements in the rate of oxidation reactions.…”

Section: Introductionmentioning

confidence: 99%

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Ferroelastic domains improve photochemical reactivity: a comparative study of monoclinic and tetragonal (Bi_1−0.5xNa_0.5x)(V_1−xMo_x)O₄ ceramics

2016

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The relative reactivities of monoclinic and tetragonal BiVO4-based ceramics are described, focusing on the contributions of ferroelastic domains and surface orientations. First, the photo-oxidation of Mn 2+ on monoclinic BiVO4 is shown to be domain selective, occurring on the set of domains that is not active for the photo-reduction of Ag + . Next, the domain and orientation dependent photochemical reduction of Ag + is investigated for two samples in the co-doped family (Bi1-0.5xNa0.5x)(V1-xMox)O4: a monoclinic sample (x = 0.05) and a tetragonal sample (x = 0.175). Like BiVO4, the x = 0.05 sample has ferroelastic domains that exhibit contrast in piezoresponse force microscopy (PFM) and exhibit domain specific reactivity. The x = 0.175 sample has no domains, no PFM contrast, and uniform grain reactivity. The orientation dependence of Ag + reduction is similar for the two samples, with surfaces near (001) being more active than others. For any given orientation, however, the monoclinic sample is quantitatively more active than the same orientation in the tetragonal sample. These collected results are consistent with the hypothesis that monoclinic-structured BiVO4 ceramics have enhanced photochemical activity owing to ferroelastic domain-selective reactivity, which allows for local separation of photogenerated carriers and redox reactions.

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Section: Methodssupporting

confidence: 67%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ferroelastic domains improve photochemical reactivity: a comparative study of monoclinic and tetragonal (Bi_1−0.5xNa_0.5x)(V_1−xMo_x)O₄ ceramics

2016

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“…Regardless, 64% is one of the best reported values of Z rxn for water oxidation by a bare BiVO 4 photoanode. 9,18 The high Z rxn,water of these Mo/T films may result from their relatively low density of in-gap defect states, the activity of the particular crystal facets exposed to the electrolyte by the textured films, 84,85 and/or fortuitously fast kinetics for the OER relative to competing processes such as recombination and photocorrosion (see below).…”

Section: à2mentioning

confidence: 99%

Textured nanoporous Mo:BiVO₄ photoanodes with high charge transport and charge transfer quantum efficiencies for oxygen evolution

Nair

Perkins

Lin

et al. 2016

Energy Environ. Sci.

155

106

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We have developed a simple spin coating method to make high-quality nanoporous photoelectrodes of monoclinic BiVO 4 and studied the ability of these electrodes to transport photogenerated carriers to oxidize sulfite and water. Samples containing molybdenum and featuring [001] out-of-plane crystallographic texture show a photocurrent and external quantum efficiency (EQE) for sulfite oxidation as high as 3.1 mA cm À2 and 60%, respectively, at 1.23 V versus reversible hydrogen electrode. By using an optical model of the electrode stack to accurately determine the fraction of electrode absorptance due to the BiVO 4 active layer, we estimate that on average 70 AE 5% of all photogenerated carriers escape recombination. A comparison of internal quantum efficiency as a function of film processing, illumination direction, and film thickness shows that electron transport is efficient and hole transport limits the photocurrent (hole diffusion length o40 nm). We find that Mo addition primarily improves electron transport and texturing mostly improves hole transport. Mo enhances electron transport by thinning the surface depletion layer or passivating traps and recombination centers at grain boundaries and interfaces, while improved hole transport in textured films may result from more efficient lateral hole extraction due to the texturing itself or the reduced density of deep gap states observed in photoemission measurements.Photoemission data also reveal that the films have bismuth-rich, vanadium-and oxygen-deficient surface layers, while ion scattering spectroscopy indicates a Bi-V-O surface termination. Without added catalysts, the plain BiVO 4 electrodes oxidized water with an initial photocurrent and peak EQE of 1.7 mA cm À2 and 30%, respectively, which equates to a hole transfer efficiency to water of 464% at 1.23 V. The electrodes quickly photocorrode during water oxidation but show good stability during sulfite oxidation and indefinite stability in the dark. By improving the hole transport efficiency and coating these nanoporous BiVO 4 films with an appropriate protective layer and oxygen evolution catalyst, it should be possible to achieve highly efficient and stable water oxidation at a practical pH.

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Reactive Oxygenated Species Generated on Iodide‐Doped BiVO₄/BaTiO₃ Heterostructures with Ag/Cu Nanoparticles by Coupled Piezophototronic Effect and Plasmonic Excitation

Zhou

Shen

Zhai

et al. 2021

Adv Funct Materials

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An effective generation of reactive oxygen species (ROS) is of interest from the perspective of environmental technology and industrial chemistry, and here piezocatalysis and photocatalysis using heterostructures based on iodide‐doped BiVO4/BaTiO3 with photodeposited Ag or Cu nanoparticles (BiVO4:I/BTO‐Ag or BiVO4:I/BTO‐Cu) is studied. The generation rates of •OH and •O2− radicals over BiVO4:I/BTO‐Ag during piezophotocatalysis are 371 and 292 µmol g−1 h−1, respectively, and significantly higher than those of sole piezocatalysis and photocatalysis. These rates are among the highest reported for the production of free radicals with the piezophototronic effect. Among the catalysts, BiVO4:I/BTO shows the highest reactivity for the production of H2O2 in piezocatalysis (with a concentration of 468 µm after 100 min of irradiation, and still constantly increasing). On BiVO4:I/BTO‐Ag and BiVO4:I/BTO‐Cu, it seems that redundant electrons and holes had reacted effectively with the generated H2O2 and in turn had reduced their activities; however, the amounts of H2O2 that are formed on BiVO4:I/BTO‐Ag or BiVO4:I/BTO‐Cu under piezophotocatalysis are superior to those of individual piezocatalysis and photocatalysis. A piezophototronic coupling via an ultrasound‐mediated and piezoelectric‐based polarization field and photoexcitation accounting for the enhanced photocatalytic activity of the iodine‐doped heterostructures with plasmonically sized Ag or Cu nanoparticles is suggested.

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The orientation dependence of the photochemical reactivity of BiVO₄

Abstract: Photochemical reduction and oxidation reactions occur on complementary and perpendicular surfaces of BiVO4 crystals.

Cited by 24 publications

References 40 publications

Ferroelastic domains improve photochemical reactivity: a comparative study of monoclinic and tetragonal (Bi_1−0.5xNa_0.5x)(V_1−xMo_x)O₄ ceramics

Ferroelastic domains improve photochemical reactivity: a comparative study of monoclinic and tetragonal (Bi_1−0.5xNa_0.5x)(V_1−xMo_x)O₄ ceramics

Textured nanoporous Mo:BiVO₄ photoanodes with high charge transport and charge transfer quantum efficiencies for oxygen evolution

Reactive Oxygenated Species Generated on Iodide‐Doped BiVO₄/BaTiO₃ Heterostructures with Ag/Cu Nanoparticles by Coupled Piezophototronic Effect and Plasmonic Excitation

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The orientation dependence of the photochemical reactivity of BiVO4

Abstract: Photochemical reduction and oxidation reactions occur on complementary and perpendicular surfaces of BiVO4 crystals.

Cited by 24 publications

References 40 publications

Ferroelastic domains improve photochemical reactivity: a comparative study of monoclinic and tetragonal (Bi1−0.5xNa0.5x)(V1−xMox)O4 ceramics

Ferroelastic domains improve photochemical reactivity: a comparative study of monoclinic and tetragonal (Bi1−0.5xNa0.5x)(V1−xMox)O4 ceramics

Textured nanoporous Mo:BiVO4 photoanodes with high charge transport and charge transfer quantum efficiencies for oxygen evolution

Reactive Oxygenated Species Generated on Iodide‐Doped BiVO4/BaTiO3 Heterostructures with Ag/Cu Nanoparticles by Coupled Piezophototronic Effect and Plasmonic Excitation

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The orientation dependence of the photochemical reactivity of BiVO₄

Ferroelastic domains improve photochemical reactivity: a comparative study of monoclinic and tetragonal (Bi_1−0.5xNa_0.5x)(V_1−xMo_x)O₄ ceramics

Ferroelastic domains improve photochemical reactivity: a comparative study of monoclinic and tetragonal (Bi_1−0.5xNa_0.5x)(V_1−xMo_x)O₄ ceramics

Textured nanoporous Mo:BiVO₄ photoanodes with high charge transport and charge transfer quantum efficiencies for oxygen evolution

Reactive Oxygenated Species Generated on Iodide‐Doped BiVO₄/BaTiO₃ Heterostructures with Ag/Cu Nanoparticles by Coupled Piezophototronic Effect and Plasmonic Excitation