Photocatalytic reactivity tuning by heterometal and addenda metal variation in Lindqvist polyoxometalates

Tucher, Johannes; Schlicht, Stefanie; Kollhoff, Fabian; Streb, Carsten

doi:10.1039/c4dt02682a

Cited by 30 publications

(22 citation statements)

References 38 publications

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“…HPLC‐grade acetonitrile (VWR) was used without further purification. The mixed‐metal clusters ( n Bu 4 N) n +2 [V n M 6− n O 19 ] (M = Mo(VI), W(VI), n = 0, 1, 2) were synthesized using an adaptation of the original synthesis reported by Klemperer et al…”

Section: Methodsmentioning

confidence: 99%

Enhanced Capacitive Energy Storage in Polyoxometalate‐Doped Polypyrrole

Herrmann

Aydemir

Nägele

et al. 2017

Adv Funct Materials

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High-performance batteries and supercapacitors require the molecular-level linkage of charge transport components and charge storage components. This study shows how redox-tunable Lindqvist-type molecular metal oxide anions [V n M 6-n O 19 ] (2+n)− (M = W(VI) or Mo(VI); n = 0, 1, 2) can be incorporated in cationic polypyrrole (PPy) conductive polymer films by means of electrochemical polymerization. Electron microscopy and (spectro-)electrochemistry show that the electroactivity and morphology of the composites can be tuned by Lindqvist anion incorporation. Reductive electrochemical "activation" of the Lindqvist-PPy composites leads to significantly increased electrical capacitance (range: ≈25-38 F g −1 , increase up to ≈25×), highlighting that this general synthetic route gives access to promising capacitive materials with suitable long-term stability. Electrochemical, electron microscopic, and Raman spectroscopic analyses together with density functional theory (DFT) calculations provide molecular-level insight into the effects of Lindqvist anion incorporation in PPy films and their role during reductive activation. The study therefore provides fundamental understanding of the principles governing the bottom-up integration of molecular components into nanostructured composites for electrochemical energy storage.The ORCID identification number(s) for the author(s) of this article can be found under http://dx.The combination of in situ (spectro-)electrochemistry and theoretical calculations allows us to provide initial molecular level understanding of the underlying activation mechanism. The study therefore provides new molecular design principles for capacitive charge storage devices.

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Section: Methodsmentioning

confidence: 99%

Enhanced Capacitive Energy Storage in Polyoxometalate‐Doped Polypyrrole

Herrmann

Aydemir

Nägele

et al. 2017

Adv Funct Materials

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“…Intriguingly, the Co‐containing TRIS‐Anderson has only been reported very recently . Thus, in contrast to the well‐documented reactivity of metal‐functionalized lacunary Keggin and Lindqvist anions, little is known about the effects of metal substitution in the Anderson anion. This information, however, is critical as metal exchange is expected to significantly affect the electronic structure of the anion and thus its reactivity in redox and light‐driven processes …”

Section: Introductionmentioning

confidence: 95%

Experimental and Theoretical Investigation of the Light‐Driven Hydrogen Evolution by Polyoxometalate–Photosensitizer Dyads

Schönweiz

Heiland

Anjass

et al. 2017

Chemistry A European J

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The visible‐light‐driven hydrogen evolution reaction (HER) by covalent photosensitizer–catalyst dyads is one of the most elegant concepts in supramolecular homogeneous solar energy conversion. The intricacies of catalyst reactivity and photosensitizer–catalyst interactions require a detailed fundamental understanding of the system to rationalize the observed reactivities. Here, we report three dyads based on the covalent imine‐bond linkage of an iridium photosensitizer and an organo‐functionalized Anderson polyoxometalate anion [MMo6O18{(OCH2)3CNH2}2]3− (M=Mn3+, Fe3+, Co3+). Modification of the central metal ion M is used to modulate the HER activity. Detailed theoretical and experimental studies examine the role of the central metal ion M and provide critical understanding of the redox activity and light‐driven HER activity of the novel dyads. Thus, the study enables a knowledge‐based optimization of HER dyads by chemical modification of the reactive metal oxide components.

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“…One of the most versatile classes of isopolyoxometalates are Lindqvist anions where the elemental composition and stoichiometry can be tuned on the molecular level, i. e. [M x M' 6-x O 19 ] nÀ (M = V, M' = W,Mo). [20] In addition, their (photo-)oxidative activity [21,22] and tuneable electronic structure [23] is well-established. Some of us have introduced the OxFA-process, where wet biomass is oxidatively converted to FA using homogeneous POM catalysts.…”

Section: Introductionmentioning

confidence: 99%

One-step Synthesizable Lindqvist−isopolyoxometalates as Promising New Catalysts for Selective Conversion of Glucose as a Model Substrate for Lignocellulosic Biomass to Formic Acid

et al. 2016

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A series of Lindqvist‐isopolyoxometalates [M6O19]n− (M=W, V) were synthesized under one‐pot conditions and were applied in the homogeneous oxidation of glucose as a model substrate for lignocellulosic biomass to formic acid (FA), which offers a new field for application of isopolyoxometalates (IPA) in catalysis. Their low molecular weight and facile accessibility in aqueous solution together with their tuneable redox properties offers a new and straightforward path for optimized precious metal free oxidation catalysts. We have systematically synthesized and characterized a series of vanadium‐ and tungsten‐based Lindqvist structures and verified their applicability in the selective oxidation of glucose to FA. Maximum FA‐yields of 39 % in aqueous solution under non‐optimized conditions were observed for Cs4[V2W4O19] and it is shown that reactivity and selectivity can be tuned by metal substitution of the cluster: FA formation is favoured with increasing V‐substitution of the [W6O19]2−‐framework. Moreover, the influence of different inorganic counter cations was investigated.

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Photocatalytic reactivity tuning by heterometal and addenda metal variation in Lindqvist polyoxometalates

Cited by 30 publications

References 38 publications

Enhanced Capacitive Energy Storage in Polyoxometalate‐Doped Polypyrrole

Enhanced Capacitive Energy Storage in Polyoxometalate‐Doped Polypyrrole

Experimental and Theoretical Investigation of the Light‐Driven Hydrogen Evolution by Polyoxometalate–Photosensitizer Dyads

One-step Synthesizable Lindqvist−isopolyoxometalates as Promising New Catalysts for Selective Conversion of Glucose as a Model Substrate for Lignocellulosic Biomass to Formic Acid

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