Photoinduced Reaction at TiO₂ Particles. Photodeposition from Ni^II Solutions with Oxalate

Abstract

In a photoinduced reaction, an intermediate produced by the reaction of a reductant R with photogenerated holes can promote a reduction reaction that is not observed in the absence of R. We illustrate this scheme by considering the reduction of Ni II at TiO 2 . In this case Ni II , which is not deposited on illuminated TiO 2 , can be reduced by the intermediate CO 2 •produced from the anodic oxidation of oxalate ion (C 2 O 4 2-) at irradiated TiO 2 in water. Irradiation of an aqueous Ni II solution containing 10 µg Ni/mL in the presence of TiO 2 particles led to 85% removal of the Ni from the solution. The mechanism of the reaction was probed by measurement of current-doubling effects for oxalate solutions at a single-crystal TiO 2 electrode.

Catalytic activity of hexagonal MoO3 modified with silver, palladium and copper

“…1b-1d provide evidence that the mean size of silver and palladium particles grown at the surface of MoO 3 microcrystals via photocatalytic deposition route was of ca. 10 nm, whereas copper deposit obtained via reduction of metal ions by radical species generated during photoconversion of oxalate [23,24] consists of the particles having ca. 5 nm in their size.…”

Effect of calcium oxalate on the photocatalytic degradation of Orange II on ZnO surface

“…/e -pair by an appropriate irradiation of ZnO. On the other hand, calcium oxalate is oxidized by reaction with a valence band hole giving rise to a radical oxalate and to yield carbon dioxide and CO 2 Á-radical (Farouzan et al 1996).…”

Heterogeneous photocatalytic reduction of Fe(VI) in UV-irradiated titania suspensions: effect of ammonia

“…The reduction rate of Fe(VI) therefore increases with the concentration of Fe(VI) in the reaction mixture, as has been found in our study (Figure 2). Other studies have also reported an acceleration in the photocatalytic reduction of metal ions with the addition of organic additives [12,[37][38][39].…”

“…However, doping TiO 2 with metal particles increases the photocatalytic activity of TiO 2 due to decrease in the efficiency of the recombination process [4,9]. The use of metal ions such as silver (I), mercury(II), copper(II), and chromium(VI) has shown to increase the photocatalytic efficiency of TiO 2 to degrade pollutants in water [10][11][12][13]. We report here the use of ferrate(VI), also known as Fe(VI) or Fe VI O 4 2) , to increase the efficiency of TiO 2 photocatalysis.…”