Evidence for Cooperativity in the Disproportionation of H2O2 Efficiently Catalyzed by a Tetranuclear Manganese Complex

Dubé, Christopher E.; Wright, David W.; Armstrong, William H.

doi:10.1002/1521-3757(20000616)112:12<2253::aid-ange2253>3.0.co;2-r

Cited by 5 publications

(3 citation statements)

References 41 publications

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“…CDot worked as a thermal catalyst to promote H 2 O 2 disproportionation. It is known that manganese,44 copper,45 and iron 46 can also catalyze H 2 O 2 disproportionation. However, the H 2 O 2 disproportionation is a slow reaction.…”

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confidence: 99%

Visible Photocatalytic Water Splitting and Photocatalytic Two-Electron Oxygen Formation over Cu- and Fe-Doped g-C₃N₄

2015

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Water splitting via two two-electron processes (the H 2 O first photocatalytically converted to H 2 and H 2 O 2 under visible light irradiation and then the H 2 O 2 disproportionation to H 2 O and O 2 by a thermal catalytic process) has attracted extensive attention recently. 1,2 Contrary to these reports, we found that not only the photocatalytic H 2 generation could be driven by visible light but also the two-electron H 2 O 2 disproportionation to form H 2 O and O 2 could also be photocatalyzed by visible light over g-C 3 N 4 catalysts. Photocatalytic H 2 , O 2 generation, and simultaneous H 2 O 2 formation in Cu/C 3 N 4 and Fe/C 3 N 4 dispersions were confirmed, about 2.1 and 1.4 μmol of H 2 and 0.8 and 0.5 μmol of O 2 evolved over Cu/C 3 N 4 and Fe/C 3 N 4 in 12 h, respectively. To prove the photocatalytic process of H 2 O 2 disproportionation, the H 2 O 2 was added as a reagent in g-C 3 N 4 , Cu/C 3 N 4 , and Fe/C 3 N 4 dispersions. The results showed that the activity of H 2 evolution decreased with the increase of H 2 O 2 concentration; the corresponding AQEs of oxygen formation were 16.1%, 42.6%, and 78.5% at 400 nm, respectively. The remarkable increase of anodic photocurrents over Fe/ C 3 N 4 /ITO and Cu/C 3 N 4 /ITO electrodes indicated that the two-electron H 2 O 2 disproportionation was catalyzed via surface photocatalytic mechanism. The ESR results implied reaction occurred by O 2 − • radical path over g-C 3 N 4 under irradiation.

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confidence: 99%

Visible Photocatalytic Water Splitting and Photocatalytic Two-Electron Oxygen Formation over Cu- and Fe-Doped g-C₃N₄

2015

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“…Traditionally, chemical doping and dye sensitizing are used to enhance light absorption [12]. Furthermore, metal-catalyst [13–15], chemical agent [16] and physical bubbling methods [17] have been reported for removing the H 2 O 2. Unfortunately, there is lack of a solution to overcome all problems at once.…”

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confidence: 99%

Green synthesis of carbon quantum dots embedded onto titanium dioxide nanowires for enhancing photocurrent

Yen¹,

Lin²,

Chen³

et al. 2017

R. Soc. open sci.

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The green synthesis of nanowired photocatalyst composed of carbon quantum dots-titanium hybrid-semiconductors, CQDs/TiO2, are reported. Where graphite-based CQDs with a size less than 5 nm are directly synthesized in pure water electrolyte by a one-step electrochemistry approach and subsequently electrodeposited onto as-prepared TiO2 nanowires through a voltage-driven reduction process. Electron paramagnetic resonance studies show that the CQDs can generate singlet oxygen and/or oxygen radicals to decompose the kinetic H2O2 intermediate species upon UV light illumination. With the effect of peroxidase-like CQDs, photocurrent density of CQDs/TiO2 is remarkably enhanced by a 6.4 factor when compared with that of as-prepared TiO2.

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“…Thus, [Mn 4 O 6 (bpea) 4 ] 4+ exhibits ligand substitution, reversible protonation, electron transfer and unusual proton‐coupled electron transfer reactions in water (13,14). Furthermore, the one‐electron reduced form [Mn 4 O 6 (bpea) 4 ] 3+ catalyzes the disproportionation of H 2 O 2 to oxygen and water (15).…”

Section: Introductionmentioning

confidence: 99%

Illumination with Ultraviolet or Visible Light Induces Chemical Changes in the Water‐soluble Manganese Complex, [Mn₄O₆(bpea)₄]Br₄

Antal

Armstrong

et al. 2009

Photochem & Photobiology

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We measured the photosensitivity of an artificial tetranuclear oxo-Mn(IV) complex, [Mn(4)O(6)(bpea)(4)]Br(4), which has an adamantane-shaped {Mn(4)O(6)}(4+) core. Illumination caused changes in the absorption spectrum of the compound consistent with a one-electron reduction in the compound. Bromide appears to be the most probable electron donor in the reaction system. Chemical modification of the cluster appears to destabilize it, predisposing it to reductive degradation. UV light was more efficient than visible light in causing the changes. The data support the suggestion that the natural oxygen-evolving Mn complex is photosensitive and can oxidize components of the oxygen-evolving complex in its excited state causing photoinhibition, and that photostability is an important issue in designing Mn complexes for artificial photosynthesis. Furthermore, light-induced oxidation of bromide by [Mn(4)O(6)(bpea)(4)](4+) may suggest that oxidation of chloride is involved in natural water splitting or has been involved during the evolution of the water-splitting enzyme.

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Evidence for Cooperativity in the Disproportionation of H2O2 Efficiently Catalyzed by a Tetranuclear Manganese Complex

Cited by 5 publications

References 41 publications

Visible Photocatalytic Water Splitting and Photocatalytic Two-Electron Oxygen Formation over Cu- and Fe-Doped g-C₃N₄

Visible Photocatalytic Water Splitting and Photocatalytic Two-Electron Oxygen Formation over Cu- and Fe-Doped g-C₃N₄

Green synthesis of carbon quantum dots embedded onto titanium dioxide nanowires for enhancing photocurrent

Illumination with Ultraviolet or Visible Light Induces Chemical Changes in the Water‐soluble Manganese Complex, [Mn₄O₆(bpea)₄]Br₄

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Evidence for Cooperativity in the Disproportionation of H2O2 Efficiently Catalyzed by a Tetranuclear Manganese Complex

Cited by 5 publications

References 41 publications

Visible Photocatalytic Water Splitting and Photocatalytic Two-Electron Oxygen Formation over Cu- and Fe-Doped g-C3N4

Visible Photocatalytic Water Splitting and Photocatalytic Two-Electron Oxygen Formation over Cu- and Fe-Doped g-C3N4

Green synthesis of carbon quantum dots embedded onto titanium dioxide nanowires for enhancing photocurrent

Illumination with Ultraviolet or Visible Light Induces Chemical Changes in the Water‐soluble Manganese Complex, [Mn4O6(bpea)4]Br4

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About

Visible Photocatalytic Water Splitting and Photocatalytic Two-Electron Oxygen Formation over Cu- and Fe-Doped g-C₃N₄

Visible Photocatalytic Water Splitting and Photocatalytic Two-Electron Oxygen Formation over Cu- and Fe-Doped g-C₃N₄

Illumination with Ultraviolet or Visible Light Induces Chemical Changes in the Water‐soluble Manganese Complex, [Mn₄O₆(bpea)₄]Br₄