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Photocatalytic processes with tungsten oxygen anion clusters.

Frontiers in bioscience : a journal and virtual library (2003-09-06)
Elias Papaconstantinou, Anastasia Hiskia, Aristidis Troupis
ABSTRACT

Polyoxometalates (POM) have a rich and promising photochemical behavior. Upon illumination at the O M CT band (i.e., in UV and near-visible area) become powerful oxidizing reagents able to oxidize various organic compounds. In the process POM undergo stepwise reduction accumulating electrons that can be subsequently delivered, via thermal reactions to a variety of oxidants. This way a great variety of organic compounds are oxidized and indeed mineralize to CO2, H2O and inorganic anions and several organic and inorganic compounds can be reduced via a photocatalytic process in which POM serve as electron relays. Thus, in principle, POM can serve as decontamination photocatalysts of aquatic media removing both organic pollutants and metal ions. Under special conditions controlled photocatalytic reactions have been reported. In addition the reduction precipitation of metal ions mediated by POM may lead to formation of metal nanoparticles in which POM serve as reducing reagents and stabilizers.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Tungsten, powder, 12 μm, 99.9% trace metals basis
Sigma-Aldrich
Tungsten, foil, thickness 0.25 mm, ≥99.9% trace metals basis
Tungsten, insulated wire, 5m, conductor diameter 0.075mm, insulation thickness 0.02mm, PTFE (polytetrafluoroethylene) insulation, 99.9%
Tungsten, insulated wire, 10m, conductor diameter 0.05mm, insulation thickness 0.008mm, polyimide insulation, 99.9%
Tungsten, microfoil, disks, 10mm, thinness 0.25μm, specific density 474μg/cm2, permanent mylar 3.5μm support, 99.95%
Tungsten, insulated wire, 0.2m, conductor diameter 0.015mm, insulation thickness 0.002mm, polyimide insulation, 99.9%
Tungsten, foil, 5m coil, thickness 0.025mm, coil width 1mm, as rolled, 99.95%
Tungsten, insulated wire, 20m, conductor diameter 0.05mm, insulation thickness 0.008mm, polyimide insulation, 99.9%
Tungsten, foil, not light tested, 50x50mm, thickness 0.004mm, 99.95%
Tungsten, foil, light tested, 150x150mm, thickness 0.05mm, as rolled, 99.95%
Tungsten, lump, 200g, max. size 5mm
Tungsten, insulated wire, 2m, conductor diameter 0.075mm, insulation thickness 0.02mm, PTFE (polytetrafluoroethylene) insulation, 99.9%
Tungsten, rod, 200mm, diameter 6.35mm, centerless ground, 99.95%
Tungsten, foil, light tested, 50x50mm, thickness 0.075mm, as rolled, 99.95%
Tungsten, foil, not light tested, 25x25mm, thickness 0.004mm, 99.95%
Tungsten, insulated wire, 2m, conductor diameter 0.025mm, insulation thickness 0.005mm, polyimide insulation, 99.9%
Tungsten, foil, 30mm disks, thickness 1.0mm, as rolled, 99.95%
Tungsten, foil, light tested, 150x150mm, thickness 0.075mm, as rolled, 99.95%
Tungsten, lump, 50g, max. size 5mm
Tungsten, insulated wire, 1m, conductor diameter 0.015mm, insulation thickness 0.002mm, polyimide insulation, 99.9%
Tungsten, microfoil, disks, 10mm, thinness 0.05μm, specific density 96μg/cm2, permanent mylar 3.5μm support, 99.95%
Tungsten, insulated wire, 2m, conductor diameter 0.0125mm, insulation thickness 0.0035mm, polyimide insulation, 99.9%
Tungsten, foil, light tested, 150x150mm, thickness 0.025mm, as rolled, 99.95%
Tungsten, microfoil, disks, 10mm, thinness 0.1μm, specific density 182μg/cm2, permanent mylar 3.5μm support, 99.95%
Tungsten, wire reel, 0.5m, diameter 1.0mm, clean, 99.95%
Tungsten, insulated wire, 2m, conductor diameter 0.015mm, insulation thickness 0.002mm, polyimide insulation, 99.9%
Tungsten, foil, not light tested, 50x50mm, thickness 0.007mm, 99.95%
Tungsten, foil, not light tested, 25x25mm, thickness 0.006mm, 99.95%
Tungsten, rod, 100mm, diameter 5.0mm, centerless ground, 99.95%
Tungsten, mesh, 100x100mm, nominal aperture 0.2mm, wire diameter 0.05mm, 100 wires/inch, open area 64%, plain weave mesh, 99.95%