Pentadecatungstotrivanadodiphosphoric heteropoly acid with Dawson structure: Synthesis, conductivity and conductive mechanism

Tong, Xia; Wu, Xiyong; Wu, Qingyin; Zhu, Weiming; Cao, Fahe; Yan, Wenfu

doi:10.1039/c2dt30466j

Cited by 57 publications

(28 citation statements)

References 36 publications

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“…We selected the representative Keggin‐type POMs with either different heteroatoms (X) or addenda atoms M (XM 12 O 40 m − where X = P, Si, and M = Mo, W, or mixed Co, W addenda) and the Dawson‐type POMs (X 2 M 18 O 62 n − where X = P and M = Mo, W, or mixed V, W addenda) to study the photosensitivity of their HPBs by using the long‐term stable membrane electrodes. The POMs were prepared according to the literatures and characterized by Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TG) curves (Figure S1, Supporting Information) . Specially speaking, they are H 4 SiW 12 O 40 (referred to as POM 1), H 3 PW 12 O 40 (POM 2), K 6 P 2 W 18 O 62 (POM 3), H 4 SiMo 12 O 40 (POM 4), H 3 PMo 12 O 40 (POM 5) and (NH 4 ) 6 P 2 Mo 18 O 62 (POM 6), as well as the substituted POMs K 6 P 2 W 15 V 3 O 62 (POM 7) and K 4 SiW 9 Co 3 O 40 (POM 8).…”

Section: Resultsmentioning

confidence: 99%

A Strategy to Obtain Long‐Term Stable Heteropoly Blues for Photosensitive Property Investigations

Chen

et al. 2018

Advanced Optical Materials

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which should have wide spectrum absorptions, anchoring groups, and appropriate energy levels in order to absorb more sunlight and excite the ground-state electrons to the excited state, then inject into the semiconductor conduction band, while the holes remain in the dye molecule form the charge separations, which ensure the effective regenerations of the photosensitizers and the unidirectional electron injections. [2] In recent decades, great efforts have been made to develop the photosensitizers with high stability, low-cost, and high solar energy conversion in the fields of photocatalysts and solar cells. [3,4] However, developing broad-spectrum photosensitizers is still a big challenge. At present, the commonly used photosensitizers including ruthenium-pyridine, porphyrin, and pure organic dyes, have efficiently improved the power conversion efficiencies (PCEs) of the DSSCs. [5] However, their large-scale productions and applications in photovoltaic industry have been limited by their high costs and the cumbersome process in the synthesis and purification of photosensitizers. [6] Furthermore, the defects of some photosensitizers in spectral absorption also restrict the utilization of sunlight. So, it is urgent to develop the photosensitizers with environment-friendly, simple preparations, low costs, and wide spectra absorptions.Heteropoly blues (HPBs) is a reductive state of polyoxometalates (POMs representing oxidation state) with fascinating structures, abundant element compositions, reversible redox properties, and wide pH stability. [7,8] The advantages of HPBs as photosensitizer are as follows: i) their wide and strong spectral absorptions in visible and near-IR regions; ii) the anchoring groups are easily to coordinated to HPBs to firmly adsorb on the semiconductor surface; iii) their energy levels involving the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO) can be adjusted by the composition, structure, and charge density to ensure the effective unidirectional electron injections and photosensitizer regenerations; [9] iv) their excellent light, thermal and electrochemical stability, their ability to accept or lose "blue" electrons without any structural transformations. As a kind of the potential photosensitizer candidates, HPBs have been increasingly recognized in terms of photocatalysis and solar cells. [10][11][12][13][14] However, the instability of HPBs in the air restricts the further research of their photosensitivity and their use as the photosensitizers in DSSCs.The photosensitizer is the soul of dye-sensitized solar cells (DSSCs), i.e., the key factor influencing the performance of DSSCs. The commonly used photo sensitizers are expensive carboxylic pyridine ruthenium-based complexes, so it is urgent to develop low-cost photosensitizers. Heteropoly blues (HPBs) could be a kind of excellent photosensitizers due to their wide spectra absorption; however, most of them are hardly stable in the air. Here, a strategy of combining the improved vacuum...

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Section: Resultsmentioning

confidence: 99%

A Strategy to Obtain Long‐Term Stable Heteropoly Blues for Photosensitive Property Investigations

Chen

et al. 2018

Advanced Optical Materials

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“…6,7 Four hybrid materials were obtained using the following processes: HPA (5.4 g) was dissolved in 30 mL of boiling water, the polymer (PVP or PEG, 0.6 g) was added to the solution, and the mixture was stirred strongly until complete dissolution of the polymer. Then the mixture was vaporized at 50 • C to remove the solvent water.…”

Section: Methodsmentioning

confidence: 99%

Preparation and Conductivity of Organic-Tungstovanadophosphoric Acid Hybrid Materials

Tong

Zhou

et al. 2012

ECS Electrochemistry Letters

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Highly conducting hybrid materials were prepared from 90 wt% tungstovanadophosphoric heteropoly acids with Dawson structure (H 7 P 2 W 17 VO 62 or H 9 P 2 W 15 V 3 O 62 , abbreviated as P 2 W 17 V or P 2 W 15 V 3 ) and 10 wt% organic polymers (polyvinylpyrrolidone, PVP or polyethylene glycol, PEG). The result reveals that the conductivities of PVP/P 2 W 17 V, PEG/P 2 W 17 V, PVP/P 2 W 15 V 3 , and PEG/P 2 W 15 V 3 are 4.70 × 10 −3 , 1.02 × 10 −2 , 7.03 × 10 −3 , and 2.00 × 10 −2 S · cm −1 at 26 • C and 75% relative humidity, respectively. Their activation energies of proton conduction are 10. 72, 9.51, 14.87 and 13.79 kJ · mol −1 , which are lower than that of the pure heteropoly acids. The mechanism of proton conduction of hybrid materials are Grotthuss mechanisms.Heteropoly acids (HPAs) and their polyoxometalates (POMs) have attracted considerable attention because of fundamental interest and potential applications. 1 They can be used in fuel cells and supercapacitors due to their properties of fast charge transfer, high conductivity, and good thermal stability. 2 However, the strong influence of humidity on their proton conductivities, diffusional problems and continuous leakage during cell operation hinder their practical utilizations. To overcome these disadvantages, HPAs have been dispersed in organic polymer matrices or formed into some of their derivatives. 3 These hybrid materials have the possibility of becoming very useful, having both these advantages of organic materials such as light weight, flexibility, and good moldability and of inorganic materials such as high strength and conductivity, heat stability, and chemical resistance. It is interesting to note that these inorganic-organic materials, in which HPAs (or POMs) were well dispersed in the polymer matrices, have been found promising for electrochemical capacitors. 4 In recent years, studies on the conductivities of hybrid materials based on HPAs (or POMs) with Keggin structure and polymer matrices have been developed rapidly. 5 Some papers have reported that as a kind of proton conductors, the conductivities of hybrid materials are closely related to HPAs' (or POMs') structures in them. However, there are few reports about these hybrid materials prepared by HPAs (or POMs) with Dawson structure and organic polymers. The HPAs with Dawson structure process many protons and water molecules which are related to their conductivities and are benefit for proton conduction. In the present work, based on HPAs (H 7 P 2 W 17 VO 62 and H 9 P 2 W 15 V 3 O 62 , abbreviated as P 2 W 17 V or P 2 W 15 V 3 ) with Dawson structure which we have prepared, we report the preparation, conductivities and conduction mechanism of four hybrid materials containing tungstovanadophosphoric HPAs with Dawson structure and PVP or PEG. ExperimentalPreparation of hybrid materials.-H 7 P 2 W 17 VO 62 · nH 2 O and H 9 P 2 W 15 V 3 O 62 · nH 2 O were synthesized according to our previous papers. 6,7 Four hybrid materials were obtained using the following processes: HPA (5.4 g) was ...

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“…The seed solution was dropped onto the substrate and spin-coated at 4500 r/min for 60 s. Then, the substrate was placed downward in the aqueous solution using 0.025 mol/L Zn(NO 3 ) 2 -Á6H 2 O, 0.025 mol/L hexamethylenetetramine, and deionized water (250 mL) at 95°C for 3 h to achieve the optimal ZnO NRs. [35][36][37][38][39]. The ITO-PET substrate was disposed like the previous step.…”

Section: Growth Of Zno Nrsmentioning

confidence: 99%

Keggin and Dawson polyoxometalates as electrodes for flexible and transparent piezoelectric nanogenerators to efficiently utilize mechanical energy in the environment

Chen

et al. 2020

Science Bulletin

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Pentadecatungstotrivanadodiphosphoric heteropoly acid with Dawson structure: Synthesis, conductivity and conductive mechanism

Cited by 57 publications

References 36 publications

A Strategy to Obtain Long‐Term Stable Heteropoly Blues for Photosensitive Property Investigations

A Strategy to Obtain Long‐Term Stable Heteropoly Blues for Photosensitive Property Investigations

Preparation and Conductivity of Organic-Tungstovanadophosphoric Acid Hybrid Materials

Keggin and Dawson polyoxometalates as electrodes for flexible and transparent piezoelectric nanogenerators to efficiently utilize mechanical energy in the environment

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