Open AccessEffective Storage of Electrons in Water by the Formation of Highly Reduced Polyoxometalate Clusters
Author(s) -
Jiajia Chen,
Laia VilàNadal,
Albert SoléDaura,
Greig Chisholm,
Takuo Minato,
Christoph Busche,
Tingting Zhao,
Balamurugan Kandasamy,
Alexey Y. Ganin,
Rachelle M. Smith,
Ian Colliard,
Jorge J. Carbó,
Josep M. Poblet,
May Nyman,
Leroy Cronin
Publication year - 2022
Publication title -
journal of the american chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.115
H-Index - 612
eISSN - 1520-5126
pISSN - 0002-7863
DOI - 10.1021/jacs.1c10584
Subject(s) - chemistry , polyoxometalate , aqueous solution , redox , cluster (spacecraft) , protonation , electron , electron paramagnetic resonance , solvated electron , chemical physics , transition metal , inorganic chemistry , crystallography , ion , nuclear magnetic resonance , radiolysis , organic chemistry , physics , quantum mechanics , computer science , programming language , catalysis
Aqueous solutions of polyoxometalates (POMs) have been shown to have potential as high-capacity energy storage materials due to their potential for multi-electron redox processes, yet the mechanism of reduction and practical limits are currently unknown. Herein, we explore the mechanism of multi-electron redox processes that allow the highly reduced POM clusters of the form {MO 3 } y to absorb y electrons in aqueous solution, focusing mechanistically on the Wells-Dawson structure X 6 [P 2 W 18 O 62 ], which comprises 18 metal centers and can uptake up to 18 electrons reversibly ( y = 18) per cluster in aqueous solution when the countercations are lithium . This unconventional redox activity is rationalized by density functional theory, molecular dynamics simulations, UV-vis, electron paramagnetic resonance spectroscopy, and small-angle X-ray scattering spectra. These data point to a new phenomenon showing that cluster protonation and aggregation allow the formation of highly electron-rich meta-stable systems in aqueous solution, which produce H 2 when the solution is diluted. Finally, we show that this understanding is transferrable to other salts of [P 5 W 30 O 110 ] 15- and [P 8 W 48 O 184 ] 40- anions, which can be charged to 23 and 27 electrons per cluster, respectively.