Water oxidation is a key reaction for the conversion of solar energy into chemical fuels, but effective water-oxidation catalysts are often based on rare and costly precious metals such as Pt, Ir or Ru. Developing strategies based on earth-abundant metals is important to explore critical aspects of this reaction, and to see whether different and more efficient applications are possible for energy systems. Herein, we present an approach to tuning a redox-active electrocatalyst based on the doping of molybdenum into the tungsten framework of [Co(HO)(PWO)], known as the Weakley sandwich. The Mo-doped framework was confirmed by X-ray crystallography, electrospray ionization mass spectrometry and inductively coupled plasma optical emission spectrometry studies. The doping of molybdenum into the robust Weakley sandwich framework leads to the oxidation of water at a low onset potential, and with no catalyst degradation, whereby the overpotential of the oxygen evolution reaction is lowered by 188 mV compared with the pure tungsten framework.
Using
solar radiation to fuel catalytic processes is often regarded
as the solution to our energy needs. However, developing effective
photocatalysts that are active under visible light has proven to be
difficult, often due to the toxicity, instability, and high cost of
suitable catalysts. We engineered a novel photoactive nanomaterial
obtained by the spontaneous electrostatic coupling of carbon nanodots
with [P2W18O62]6–, a molecular catalyst belonging to the class of polyoxometalates.
While the former are used as photosensitizers, the latter was chosen
for its ability to catalyze reductive reactions such as dye decomposition
and water splitting. We find the electron transfer within the nanohybrid
to be so efficient that a charge-separated state is formed within
120 fs from photon absorption. These results are a cornerstone in
the engineering of a new class of nanodevices, which are nontoxic,
are inexpensive, and can carry out solar-driven catalytic processes.
We report the formation of two polyoxotungstates of the general formula [M6(PW6O26)(α-P2W15O56)2(H2O)2](23-) (M = Co(II) or Mn(II)), which contain {PW6} fragments generated from the [P2W15O56](12-) precursor, which demonstrates for the first time the transformation of a Dawson lacunae into a Keggin lacunary building block. Solution analysis of the clusters has been conducted via electrospray ionisation mass spectrometry.
Among the photocatalysts which could be used for converting solar energy, polyoxometalates are often regarded as ideal candidates because of their remarkable performances in photocatalytic water splitting and photodegradation of...
Rearrangement of {-P 2W15} to {PW6} Moieties During the Assembly of Transition-Metal-Linked Polyoxometalate Clusters. -Compounds (IV) and (VI) contain {PW 6} fragments generated from the [P2W15O56] 12precursor, which demonstrates the transformation of a Dawson lacunae into a Keggin lacunary building block. The compounds crystallize in the triclinic space group P1 with Z = 2 and display a V-shaped sandwich structure. The anionic units consist of two {-P 2W15} units each connected by three transition metal atoms to a central {PW 6} species, creating a bent architecture. The compound Na5Li20[W45Mn9P8O17(OH)5(H2O)6]·60H2O (space group P1, Z = 2) is obtained a few times at pH values > 7.5 in very low yield but could not be fully characterized due to lack of material. -(MARTIN-SABI, M.; WINTER, R. S.; LYDON, C.; CAMERON, J. M.; LONG, D.-L.; CRONIN*, L.; Chem. Commun. (Cambridge) 52 (2016) 5, 919-921, http://dx.
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