Photoreduction of methyl viologen in aqueous neutral solution without additives

Ebbesen, Thomas W.; Levey, Gerrit; Patterson, L. K.

doi:10.1038/298545a0

Cited by 78 publications

(59 citation statements)

References 35 publications

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“…S16). The reduction potential for DQ 2+ [−0.7 V vs. normal hydrogen electrode (NHE)] is more negative than that for MV 2+ (−0.44 V vs. NHE) (91), indicating that the conduction band electron from CdSe NCs must be more negative than −0.7 V vs. NHE. These measurements are consistent with published cyclic voltammetric studies that indicate a reduction potential more negative than −1 V for CdSe NCs of this size (92 -and related dithiolenes in terms of the steps leading to H 2 generation (94).…”

Section: Use Of Ni(pyridylthiolate)mentioning

confidence: 99%

Photogeneration of hydrogen from water using CdSe nanocrystals demonstrating the importance of surface exchange

Das

Han

Haghighi

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

129

139

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Unique tripodal S-donor capping agents with an attached carboxylate are found to bind tightly to the surface of CdSe nanocrystals (NCs), making the latter water soluble. Unlike that in similarly solubilized CdSe NCs with one-sulfur or two-sulfur capping agents, dissociation from the NC surface is greatly reduced. The impact of this behavior is seen in the photochemical generation of H 2 in which the CdSe NCs function as the light absorber with metal complexes in aqueous solution as the H 2 -forming catalyst and ascorbic acid as the electron donor source. This precious-metalfree system for H 2 generation from water using [Co(bdt) 2 ]− (bdt, benzene-1,2-dithiolate) as the catalyst exhibits excellent activity with a quantum yield for H 2 formation of 24% at 520 nm light and durability with >300,000 turnovers relative to catalyst in 60 h.photochemistry | solar energy | catalysis | water splitting | quantum dots A rtificial photosynthesis (AP) represents an important strategy for energy conversion from sunlight to storage in chemical bonds (1-4). Unlike natural photosynthesis in which CO 2 + H 2 O are converted into carbohydrates and O 2 , the key energy-storing reaction in AP is the splitting of water into its constituent elements of hydrogen and oxygen (5-16). As a redox reaction, water splitting can be divided into two half-reactions, of which the light-driven generation of H 2 is the reductive component. Many systems for the photogeneration of H 2 have been described over the years and they typically consist of a light absorber, a catalyst for H 2 formation, and sources of protons and electrons. For systems that function in aqueous media, the protons are provided by water, whereas for nonaqueous systems, the protons are provided by weak, generally organic acids. The source of electrons in these photochemical systems is generally a sacrificial electron donor-that is, a compound that decomposes following one electron oxidation.Reports of the light-driven generation of hydrogen date back more than 30 y, beginning with a multicomponent system containing [Ru(bpy) 3 ] 2+ (where bpy is 2,2′-bipyridine) as the chromophore or photosensitizer (PS) and colloidal Pt as the catalyst for making H 2 from protons and electrons (17). In these and many subsequent systems, electron mediators were used to accept an electron from the excited chromophore, PS*-thereby serving as an oxidative quencher-and transfer it to the catalyst. Whereas two of the initial mediators were bpy complexes of rhodium and cobalt (17, 18), the overwhelming majority of electron mediators in these systems were dialkylated 2,2′-and 4,4′-bipyridines and their derivatives (19)(20)(21)(22). The most extensively used of these mediators was methyl viologen (MV 2+ , dimethyl-4,4′-bipyridinium, usually as its chloride salt). These mediators were subsequently found to undergo deactivation in their role by hydrogenation (23, 24). The sacrificial electron donors used in these studies depended on system pH and were generally based on compounds having tertiary amine func...

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Section: Use Of Ni(pyridylthiolate)mentioning

confidence: 99%

Photogeneration of hydrogen from water using CdSe nanocrystals demonstrating the importance of surface exchange

Das

Han

Haghighi

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

129

139

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“…The reversible color changes were observed repeatedly. When PVP, a polar aprotic polymer, was used as solid matrix, bpy-V 2+ also developed with higher intensity compared to that of PVA polymer with the f 1/2 of 0,3 h. The reversible photoreduction in the polymer matrix is considered to proceed in a similar way to that in solution 12,13) : V 2+ is photochemically reduced by electron transfer from the counter anion (Scheme 2, Eq. 1).…”

Section: Resultsmentioning

confidence: 98%

Synthesis and photoinduced coloration of ferric bipyridine complex linked viologen units in a polymer matrix

Jin

Haramoto

Nanasawa³

1999

Macromol. Rapid Commun.

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“…The MV + . radical, formed after electron transfer, is blue in color and has a strong absorption in the visible re- gion [31], while in the case of O 2 and N 2 O fading of the color takes place. As mentioned earlier, metal particles were trapped in the gel network, thus it was interesting to see whether the metal particles incorporated in the polymer matrix could still transfer electrons to MV 2+ .…”

Section: Resultsmentioning

confidence: 99%

Synthesis and stabilization of cadmium and thallium metal nanoparticles in a polymer matrix

Kapoor¹,

Joshi²,

Mukherjee³

2003

Journal of Colloid and Interface Science

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Photoreduction of methyl viologen in aqueous neutral solution without additives

Cited by 78 publications

References 35 publications

Photogeneration of hydrogen from water using CdSe nanocrystals demonstrating the importance of surface exchange

Photogeneration of hydrogen from water using CdSe nanocrystals demonstrating the importance of surface exchange

Synthesis and photoinduced coloration of ferric bipyridine complex linked viologen units in a polymer matrix

Synthesis and stabilization of cadmium and thallium metal nanoparticles in a polymer matrix

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