BiVO<sub>4</sub> {010} and {110} Relative Exposure Extent: Governing Factor of Surface Charge Population and Photocatalytic Activity

Tan, Hui Ling; Wen, Xiaoming; Amal, Rose; Ng, Yun Hau

doi:10.1021/acs.jpclett.6b00428

Cited by 238 publications

(177 citation statements)

References 43 publications

(69 reference statements)

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“…The light absorption and X‐ray diffraction (XRD) results (Figure S2) indicate the formation of monoclinic scheelite BiVO 4 with a bandgap of 2.4 eV. Accordingly, the exposed facets of the decahedral microplate can be inferred as {010} and {110} respectively . As already demonstrated elsewhere, the {010} facets favor proton reduction and thus can be regarded as R‐facets, whereas {110} facets favor water oxidation and thus can be recognized as O‐facets, as schematically illustrated in Figure e .…”

Section: Figuresupporting

confidence: 55%

Effect of Facet‐Selective Assembly of Cocatalyst on BiVO₄ Photoanode for Solar Water Oxidation

et al. 2019

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Rational assembly of cocatalysts on crystal‐based photocatalysts with anisotropic facets, namely the reduction cocatalyst on the reduction facets and oxidation cocatalyst on the oxidation facets, can enhance the photocatalytic activity remarkably. However, this strategy of selective loading of cocatalysts on crystal‐facet engineered photoelectrodes is rarely discussed in photoelectrocatalysis (PEC). Herein, we fabricated BiVO4 microcrystal photoanodes with simultaneous exposure of oxidation {110} and reduction {010} facets to study the effect of facet‐selective assembly of cocatalysts on the activity of PEC water oxidation. By elaborative photodeposition, identical cocatalysts of MnOx were selectively loaded on the reduction, the oxidation and all the facets of BiVO4 photoanodes (respectively designated as R‐BVO, O‐BVO and O/R‐BVO). We found that MnOx facilitates the charge separation in BiVO4 more significantly on the oxidation facets than on the reduction ones, contributing to the net increase in photocurrent of O‐BVO being as 5.2 and 2.2 times that of R‐BVO and O/R‐BVO, respectively. Surface photovoltage analysis reveals that the interaction between the inherent built‐in electric field in BiVO4 crystals and the additive electric filed induced by the MnOx was account for the difference. Our work emphasizes the effect of facet‐selective assembly of cocatalyst in PEC systems, which may guide the rational design of highly efficient photoelectrodes for solar energy conversion.

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Section: Figuresupporting

confidence: 55%

Effect of Facet‐Selective Assembly of Cocatalyst on BiVO₄ Photoanode for Solar Water Oxidation

et al. 2019

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“…Dual‐faceted BiVO 4 with dominating oxidation functional {110} facets was synthesized using the method reported in our recent work and annealed under Ar atmosphere at different temperatures, namely, 300, 500, and 700 °C. Herein, the treated BiVO 4 samples are denoted as Ar T , where T represents the annealing temperature.…”

Section: Resultsmentioning

confidence: 99%

“…Synthesis of BiVO 4 : Dual‐faceted BiVO 4 particles were prepared using the same method reported in recent papers with an aqueous nitric acid (HNO 3 ) solution of 1.00 m . For annealing treatment, the BiVO 4 powder was heated at different temperatures (300, 500, and 700 °C) for 2 h in a tube furnace equipped with continuous flow of Ar gas.…”

Section: Methodsmentioning

confidence: 99%

Enhancing the Photoactivity of Faceted BiVO₄ via Annealing in Oxygen‐Deficient Condition

Tan

Suyanto

Denko

et al. 2016

Part & Part Syst Charact

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Thermal annealing of metal oxides in oxygen‐deficient atmosphere, particularly reducing hydrogen gas, has been demonstrated to induce oxygen vacancy formation for enhanced photoactivity of the materials. Here, it is demonstrated that argon annealing (another prevalently used oxygen‐deficient gas) in the temperature range of 300–700 °C greatly affects the activity of dual‐faceted BiVO4 microcrystals for photocatalytic O2 generation and photocurrent generation. While treatment at 300 °C has little to no effect, higher temperatures of 500 and 700 °C significantly improve the crystallinity, alter the local structure distortion, and reduce the bandgap energy of the treated BiVO4. The higher temperature treatment also favors formation of new subgap states attributed to oxygen vacancies, as supported by surface photovoltage and electron paramagnetic resonance spectroscopies. Despite the most profound improvements in structural, optical, and electronic properties displayed by the 700 °C‐treated BiVO4, the sample annealed at 500 °C exhibits the highest photoactivity. The lower activity of the 700 °C‐treated BiVO4 is ascribed to the creation of bismuth vacancies and the loss of well‐defined crystal facets, contributing to impeded electron transport and poor charge separation.

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“…TCSPC characterization was conducted at 20 K to reduce interference from the lattice oscillation and the defect states in metal oxides. The slow component originates from the electron-hole recombination, [44,45] and its time constant (τ 2 ) is longer for Au-BVO (4.25 ns) than for BVO (2.69 ns). The fitted parameters for the Au-BVO and BVO photoanodes are listed in Figure 5c.…”

Section: Charge Carrier Dynamicsmentioning

confidence: 99%

“…The longer τ 2 and τ ave values for Au-BVO indicate that 4). [45] Figure 5b shows the time-resolved TA profiles for BVO and Au-BVO fitted with a single-exponential function. Here, the charge transport efficiency was obtained using η transport = J scavenger /J abs , and the charge transfer efficiency was obtained using η transfer = J water /J scavenger .…”

Section: Charge Carrier Dynamicsmentioning

confidence: 99%

Enhancing Mo:BiVO₄ Solar Water Splitting with Patterned Au Nanospheres by Plasmon‐Induced Energy Transfer

Kim

Shi

Jeong

et al. 2017

Advanced Energy Materials

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PEC cells demands the development of stable, economical, and efficient photoanodes. Stable, earth-abundant metal oxides such as TiO 2 , WO 3 , Fe 2 O 3 , and BiVO 4 are popular photoanode candidates. [2,3] However, these metal oxide photoanodes exhibit poor efficiency because they cannot achieve simultaneously high light absorption, charge separation, and charge transfer efficiencies. [4][5][6] One common strategy for improving these metal oxide photoanodes is to decorate them with various plasmonic metals, such as metal nanoparticles or nanorods, to introduce nearfield localized surface plasmon resonance (LSPR) and/or surface plasmon polaritons (SPP). [7][8][9][10][11][12][13][14][15][16][17][18] Many studies on these plasmonic metal nanostructures have focused on the light absorption enhancement effect from LSPR and SPP. [9,[19][20][21][22][23][24][25][26] In addition, LSPR can improve the performance of metal oxide photoanodes through plasmonic energy transfer through two mechanisms: direct electron transfer (DET) and plasmon-induced resonant energy transfer (PIRET). [9,21] DET refers to the hot-electrons injection from plasmonic metal nanoparticles to the conduction band of neighboring metal oxides, and it requires direct contact between metal and metal oxides. [9] PIRET was recently proposed by several pioneering studies. [9,21] PIRET utilizes the nonradiative dipole-dipole coupling between metals and metal oxides to Plasmonic metal nanostructures have been extensively investigated to improve the performance of metal oxide photoanodes for photoelectrochemical (PEC) solar water splitting cells. Most of these studies have focused on the effects of those metal nanostructures on enhancing light absorption and enabling direct energy transfer via hot electrons. However, several recent studies have shown that plasmonic metal nanostructures can improve the PEC performance of metal oxide photoanodes via another mechanism known as plasmon-induced resonant energy transfer (PIRET). However, this PIRET effect has not yet been tested for the molybdenum-doped bismuth vanadium oxide (Mo:BiVO 4 ), regarded as one of the best metal oxide photoanode candidates. Here, this study constructs a hybrid Au nanosphere/Mo:BiVO 4 photoanode interwoven in a hexagonal pattern to investigate the PIRET effect on the PEC performance of Mo:BiVO 4 . This study finds that the Au nanosphere array not only increases light absorption of the photoanode as expected, but also improves both its charge transport and charge transfer efficiencies via PIRET, as confirmed by time-correlated single photon counting and tran-

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BiVO₄ {010} and {110} Relative Exposure Extent: Governing Factor of Surface Charge Population and Photocatalytic Activity

Cited by 238 publications

References 43 publications

Effect of Facet‐Selective Assembly of Cocatalyst on BiVO₄ Photoanode for Solar Water Oxidation

Effect of Facet‐Selective Assembly of Cocatalyst on BiVO₄ Photoanode for Solar Water Oxidation

Enhancing the Photoactivity of Faceted BiVO₄ via Annealing in Oxygen‐Deficient Condition

Enhancing Mo:BiVO₄ Solar Water Splitting with Patterned Au Nanospheres by Plasmon‐Induced Energy Transfer

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BiVO4 {010} and {110} Relative Exposure Extent: Governing Factor of Surface Charge Population and Photocatalytic Activity

Cited by 238 publications

References 43 publications

Effect of Facet‐Selective Assembly of Cocatalyst on BiVO4 Photoanode for Solar Water Oxidation

Effect of Facet‐Selective Assembly of Cocatalyst on BiVO4 Photoanode for Solar Water Oxidation

Enhancing the Photoactivity of Faceted BiVO4 via Annealing in Oxygen‐Deficient Condition

Enhancing Mo:BiVO4 Solar Water Splitting with Patterned Au Nanospheres by Plasmon‐Induced Energy Transfer

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BiVO₄ {010} and {110} Relative Exposure Extent: Governing Factor of Surface Charge Population and Photocatalytic Activity

Effect of Facet‐Selective Assembly of Cocatalyst on BiVO₄ Photoanode for Solar Water Oxidation

Effect of Facet‐Selective Assembly of Cocatalyst on BiVO₄ Photoanode for Solar Water Oxidation

Enhancing the Photoactivity of Faceted BiVO₄ via Annealing in Oxygen‐Deficient Condition

Enhancing Mo:BiVO₄ Solar Water Splitting with Patterned Au Nanospheres by Plasmon‐Induced Energy Transfer