Merck

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
钨, wire, diam. 0.25 mm, ≥99.9% trace metals basis
Sigma-Aldrich
钨, foil, thickness 0.05 mm, ≥99.9% trace metals basis
Sigma-Aldrich
钨, wire, diam. 0.5 mm, ≥99.9% trace metals basis
Sigma-Aldrich
钨, wire, diam. 1.0 mm, 99.99% trace metals basis
Sigma-Aldrich
钨, foil, thickness 0.25 mm, ≥99.9% trace metals basis
钨, mesh, 50x50mm, nominal aperture 0.2mm, wire diameter 0.05mm, 100 wires/inch, open area 64%, plain weave mesh, 99.95%
Sigma-Aldrich
钨, foil, thickness 0.127 mm, ≥99.9% trace metals basis
钨, wire reel, 5m, diameter 0.005mm, gold plated, 99.95%
Sigma-Aldrich
钨, foil, thickness 0.5 mm, ≥99.9% trace metals basis
钨, wire reel, 25m, diameter 0.05mm, clean, 99.95%
钨, foil, light tested, 100x100mm, thickness 0.05mm, as rolled, 99.95%
钨, lump, 50g, max. size 5mm
钨, wire, straight, 300mm, diameter 0.10mm, 99.9+%
钨, rod, 100mm, diameter 1.6mm, centerless ground, 99.95%
钨, wire reel, 10m, diameter 0.5mm, clean, 99.95%
钨, wire, straight, 1000mm, diameter 0.30mm, 99.9+%
钨, wire, straight, 300mm, diameter 0.25mm, 99.9+%
钨, wire reel, 25m, diameter 0.15mm, clean, 99.95%
钨, wire reel, 25m, diameter 0.1mm, clean, 99.95%
钨, insulated wire, 1m, conductor diameter 0.075mm, insulation thickness 0.02mm, PTFE (polytetrafluoroethylene) insulation, 99.9%
钨, foil, 100x100mm, thickness 0.125mm, as rolled, 99.95%
钨, foil, 100x100mm, thickness 0.15mm, as rolled, 99.95%
钨, foil, 100x100mm, thickness 0.1mm, as rolled, 99.95%
钨, foil, 100x100mm, thickness 0.2mm, as rolled, 99.95%
钨, foil, 100x100mm, thickness 0.3mm, as rolled, 99.95%
钨, foil, 100x100mm, thickness 0.5mm, as rolled, 99.95%
钨, foil, 100x100mm, thickness 1.0mm, as rolled, 99.95%
钨, foil, 100x100mm, thickness 2.0mm, as rolled, 99.95%
钨, foil, 150x150mm, thickness 0.125mm, as rolled, 99.95%
钨, foil, 150x150mm, thickness 0.15mm, as rolled, 99.95%