Communication Dans Un Congrès Année : 2018

The Relevance of Polyoxometalates in Electrochemistry and Electro-catalysis

Résumé

Polyoxometalates (POMs) may be considered molecular oxides consisting of single clusters of several transition metal atoms of various elements exhibiting well defined shapes (such as the Keggin- and the Dawson-type POMs [1]). Since transition metals may have different oxidation states, POMs are involved in a plethora of redox processes which may be addressed by Electrochemistry, and have found several applications in Electro-catalysis [2]. Some examples of the rich and varied redox behaviour of POMs are given. The electrochemical behaviour of POMs is influenced by several parameters such as the hetero-element size and charge [3], the nature [4] and the position (eg 1 or 2 isomer [4,5]) of the substituent cations and the pH when (de)protonation is coupled to electron transfer [6]. Some observed trends have been confirmed and rationalised by theoretical approaches [7], namely with more complex structures like sandwich-type POMs with the equatorial plane composed of atoms of two elements from the first transition row [8]. In some cases, Electrochemistry succeeded in distinguishing internally from externally located cations forming the central plane of sandwich-type POMs [9]. Processes like the reduction of NOx or O2 [10], and the hydrogen evolution reaction (HER) have been rendered more efficient using POMs as electro-catalysts, in the latter case using organic-inorganic hybrids [11,12] (Figure). The number of composites obtained with POMs and carbon nanomaterials (POM@C) has been growing and some analytical applications thereof are promising [13,14]. References [1] R. Contant, G. Hervé Rev. Inorg. Chem. 2002, 22, 63-111. [2] B. Keita, L. Nadjo Electrochemistry of isopoly and heteropoly oxometalates. Bard, A.J. & Stratmann, M. Encyclopedia of Electrochemistry, Wiley-VCH, 2006, Vol. 7, pp. 607-700. [3] I.-M. Mbomekalle et al., Inorg. Chem. 2010, 49, 7001–7006. [4] B. Keita et al., J. Electroanal. Chem. 1999, 478, 76-82. [5] B. Keita et al., New J. Chem. 2002, 26, 1314–1319. [6] N. Vilà et al., Inorg. Chem. 2012, 51, 6129–6138. [7] L. Parent et al., Inorg. Chem. 2014, 53, 5941–5949. [8] F. Doungmene et al., Electrochim. Acta 2014, 125, 674–682. [9] I.-M. Mbomekalle et al., Eur. J. Inorg. Chem. 2009, 34, 5194–5204. [10] M. Ibrahim et al., Inorg. Chem. 2015, 54, 6136–6146. [11] B. Nohra et al., J. Am. Chem. Soc. 2011, 133, 13363–13374. [12] G. Rousseau et al., Cryst. Growth Des. 2015, 15, 449–456. [13] D.M. Fernandes et al., Inorganics 2015, 3, 178–193. [14] S. Zhang et al., J. Colloid Interface Sci. 2018, 514, 507–516.

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hal-04273516 , version 1 (07-11-2023)

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  • HAL Id : hal-04273516 , version 1

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Pedro de Oliveira. The Relevance of Polyoxometalates in Electrochemistry and Electro-catalysis. CLUSPOM, Jun 2018, Gif-sur-Yvette, France. ⟨hal-04273516⟩
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