Role of Alkali Metal in BiVO<sub>4</sub> Crystal Structure for Enhancing Charge Separation and Diffusion Length for Photoelectrochemical Water Splitting

Prasad, Umesh; Prakash, Jyoti; Shi, Xuan; Sharma, Sandeep; Peng, Xihong; Kannan, Arunachala Mada

doi:10.1021/acsami.0c16519

Cited by 33 publications

(28 citation statements)

References 47 publications

(94 reference statements)

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“…Among various candidates, bismuth vanadate (BiVO 4 ) has been attracted particular attentions owing to its appropriate bandgap (2.4 eV) and suitable band-edge positions 6 – 10 . However, suffering from the high charge-recombination and sluggish oxygen evolution reaction (OER) kinetics, most of reported photocurrent densities of BiVO 4 photoanodes are far below the theoretical expectation (7.5 mA cm −2 , AM 1.5 G illumination, 100 mW cm −2 ) 11 – 13 . During past decades, diverse strategies have been developed to improve the PEC activities of BiVO 4 photoanodes, including elemental doping 14 – 16 , facet tailoring 17 – 19 , and hetero-junction 20 – 24 , etc.…”

Section: Introductionmentioning

confidence: 94%

Nitrogen-incorporation activates NiFeOx catalysts for efficiently boosting oxygen evolution activity and stability of BiVO4 photoanodes

et al. 2021

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Developing low-cost and highly efficient catalysts toward the efficient oxygen evolution reaction (OER) is highly desirable for photoelectrochemical (PEC) water splitting. Herein, we demonstrated that N-incorporation could efficiently activate NiFeOx catalysts for significantly enhancing the oxygen evolution activity and stability of BiVO4 photoanodes, and the photocurrent density has been achieved up to 6.4 mA cm−2 at 1.23 V (vs. reversible hydrogen electrode (RHE), AM 1.5 G). Systematic studies indicate that the partial substitution of O sites in NiFeOx catalysts by low electronegative N atoms enriched the electron densities in both Fe and Ni sites. The electron-enriched Ni sites conversely donated electrons to V sites of BiVO4 for restraining V5+ dissolution and improving the PEC stability, while the enhanced hole-attracting ability of Fe sites significantly promotes the oxygen-evolution activity. This work provides a promising strategy for optimizing OER catalysts to construct highly efficient and stable PEC water splitting devices.

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Section: Introductionmentioning

confidence: 94%

Nitrogen-incorporation activates NiFeOx catalysts for efficiently boosting oxygen evolution activity and stability of BiVO4 photoanodes

et al. 2021

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“…Very recently, Prasad et al examined the performance of Na and K doping (alkali metals) in the BiVO 4 structure to improve photon absorption, D L of e − -h + pair, and effective charge transfer for PEC water splitting. [116] Na:BiVO 4 with Co-based catalyst layer showed the photocurrent density of 3.2 mA cm −2 at 1.23 V RHE by effectively utilizing absorbed photon toward water oxidation with η sep of ≈92% (Figure 8h). By employing Doppler broadening spectroscopy measurements, the defect parameter S versus positron implantation energy (E) plots of all the samples showed the defect analysis to calculate charge particle's D L via positron shelling on the photoanode surface.…”

Section: Doping Engineeringmentioning

confidence: 99%

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confidence: 99%

Emerging Surface, Bulk, and Interface Engineering Strategies on BiVO₄ for Photoelectrochemical Water Splitting

Gaikwad

Suryawanshi

Ghorpade

et al. 2021

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Therefore, an ever-growing demand for sustainable and environmentally-friendly energy technologies are prompting scientists to explore alternative approaches to reduce the carbon footprint. [2] Among the different sustainable energy sources, solar energy is an inexhaustible source of energy (173000 Terawatt (TW), almost 10 000 times of 17.7 TW, global energy consumption in 2020) and the largest currently available on earth with a ubiquitous distribution worldwide. [3] However, its decentralized and intermittent nature poses a great challenge to our energy needs. [4] Artificial photosynthesis, imitating a natural photosynthesis, where the harvesting of sunlight directly into chemical bonds (hydrogen, (H 2 ) fuel) is a highly promising approach to address the serious issue like air pollution, greenhouse gas emission, etc. Artificial photosynthesis by means of photoelectrochemical (PEC) water splitting has been studied extensively to split water using sunlight and semiconductor into oxygen (O 2 ) and H 2 , where the generated H 2 can be stored and transported to other energy conversion systems. [5] In recent years, PEC water splitting turned out to be an elegant and ecological way to generate clean H 2 fuel. Despite having mature and commercialized technologies, photovoltaic-electrochemical (PV-EC) water splitting systems have the most significant complications in PV designs. [6] In a photocatalytic (PC) water splitting system, on the other hand, both H 2 and O 2 are generated on the same surface of the PC particles, and hence in most cases, backward complex reactions like hydrogen oxidation reaction and oxygen reduction reaction occur quickly, lowering the solar to H 2 (STH) conversion efficiency. [7] In comparison to the PC system, the physical separation of oxidation and reduction species in PEC cells makes them more practical, effective, and safer. Moreover, the PEC cells have an electrode/electrolyte interface that performs simultaneous roles of light-harvesting and electrolysis in a single reactor. Consequently, the large-scale application of PEC cells is the most achievable, even at lower operating temperature as it opens up the opportunity to improve efficiency and reduce costs through the nature of its device structure. In particular, a recent assessment of its practicability has shown that the lifespan (i.e., stability), efficiency, and capital cost of The photoelectrochemical (PEC) cell that collects and stores abundant sunlight to hydrogen fuel promises a clean and renewable pathway for future energy needs and challenges. Monoclinic bismuth vanadate (BiVO 4 ), having an earthabundancy, nontoxicity, suitable optical absorption, and an ideal n-type band position, has been in the limelight for decades. BiVO 4 is a potential photoanode candidate due to its favorable outstanding features like moderate bandgap, visible light activity, better chemical stability, and cost-effective synthesis methods. However, BiVO 4 suffers from rapid recombination of photogenerated charge carriers that have impeded further imp...

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“…good performance as a water splitter. 5,15,16 Single BVO has poor electronic conductivity. Numerous BVO photoelectrodes have been prepared in bulk or powder form; however, they showed an undesirable recombination of bulk electron−holes due to large grain boundaries and poor particle-to-particle or conducting substrate connection.…”

Section: Introductionmentioning

confidence: 99%

“…Photoelectrochemical (PEC) water splitting is a simple approach for sustainable H 2 production from sunlight and water resources. Despite its considerable potential, the practical realization of this process is hindered by the characteristics of the photoelectrodes: (i) moderate solar-to-hydrogen conversion efficiency, , (ii) sluggish oxygen evolution reaction kinetics, and (iii) the involvement of complex four-electron chemistry necessitating a large overpotential to drive PEC reactions. − These challenges encourage research on improving the functionality of existing materials or the development of economical photoelectrocatalysts with enhanced light absorption, electron–hole separation, and stability.…”

Section: Introductionmentioning

confidence: 99%

Interstitial M⁺ (M⁺ = Li⁺ or Sn⁴⁺) Doping at Interfacial BiVO₄/WO₃ to Promote Photoelectrochemical Hydrogen Production

Patil

Lee

Park

et al. 2021

ACS Appl. Energy Mater.

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Doping metals together with heterostructure assemblages is critical to address the challenges encountered while using bismuth vanadate (BVO) to yield improved light-harvesting, charge transfer, and solar-to-hydrogen conversion efficiency. To date, most approaches have focused on substitutional doping using hexavalent metal ions (Mo 6+ and W 6+ ) at vanadium or bismuth sites to improve the photoelectrochemical (PEC) performance. Unlike conventional substitution, which produces V-substituted sites that function as hole traps and reduce the activity, herein, we used a simple hydrothermal and metal−organic decomposition approach to introduce interstitial [Li + or Sn 4+ ] n -doping in BVO (n = 0.25, 0.5, 1.0, 1.5, and 2.0 mM) interfaced with tungsten oxide (WO). The resulting Sn-doped BVO/WO (0.5 mM) shows a reproducible photocurrent density of 1.65 ± 0.07 mA cm −2 and 4.28 ± 0.15 mA cm −2 at 1.23 V RHE for water oxidation and sulfite oxidation, respectively, with a superior quantum efficiency (60% at 470 nm) and long-term durability (>10000 s) under standard AM 1.5 G light irradiation (1 sun). The results show that the Sn-doped BVO/WO exhibited an enhanced PEC performance approximately three times better than that of pristine BVO/WO, thus enabling continuous H 2 production (∼800 μmol•cm −2 ) and highlighting the beneficial role of strategically controlled interstitial dopant concentration. Mott−Schottky analysis revealed an increase in the donor concentration for Li−BVO/WO (∼2.3-fold) and Sn−BVO/WO (3.5fold), related to the reference BVO/WO photoelectrode. This work highlights the use of low-cost dopants and heterojunction photocatalysts to carry out hydrogen evolution reactions at a significantly improved rate.

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Role of Alkali Metal in BiVO₄ Crystal Structure for Enhancing Charge Separation and Diffusion Length for Photoelectrochemical Water Splitting

Cited by 33 publications

References 47 publications

Nitrogen-incorporation activates NiFeOx catalysts for efficiently boosting oxygen evolution activity and stability of BiVO4 photoanodes

Nitrogen-incorporation activates NiFeOx catalysts for efficiently boosting oxygen evolution activity and stability of BiVO4 photoanodes

Emerging Surface, Bulk, and Interface Engineering Strategies on BiVO₄ for Photoelectrochemical Water Splitting

Interstitial M⁺ (M⁺ = Li⁺ or Sn⁴⁺) Doping at Interfacial BiVO₄/WO₃ to Promote Photoelectrochemical Hydrogen Production

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Role of Alkali Metal in BiVO4 Crystal Structure for Enhancing Charge Separation and Diffusion Length for Photoelectrochemical Water Splitting

Cited by 33 publications

References 47 publications

Nitrogen-incorporation activates NiFeOx catalysts for efficiently boosting oxygen evolution activity and stability of BiVO4 photoanodes

Nitrogen-incorporation activates NiFeOx catalysts for efficiently boosting oxygen evolution activity and stability of BiVO4 photoanodes

Emerging Surface, Bulk, and Interface Engineering Strategies on BiVO4 for Photoelectrochemical Water Splitting

Interstitial M+ (M+ = Li+ or Sn4+) Doping at Interfacial BiVO4/WO3 to Promote Photoelectrochemical Hydrogen Production

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Role of Alkali Metal in BiVO₄ Crystal Structure for Enhancing Charge Separation and Diffusion Length for Photoelectrochemical Water Splitting

Emerging Surface, Bulk, and Interface Engineering Strategies on BiVO₄ for Photoelectrochemical Water Splitting

Interstitial M⁺ (M⁺ = Li⁺ or Sn⁴⁺) Doping at Interfacial BiVO₄/WO₃ to Promote Photoelectrochemical Hydrogen Production