Gold photocatalysis

Solar-grade silicon, production of, 22 507-508 Solar heat control, use of gold in, 12 703 Solarization effect, 19 203 Solar photocatalysis, 23 23-24 Solar photocatalytic detoxification, 19 76 Solar photocatalytic processes, 19 100-101 Solar photocatalytic reactor, using deposited titania, 19 99 Solar photoreactors, 19 95-99 Solar salt harvesting, 22 802, 806-808 Solar spectrum, 23 2 Solar still, 26 89-92 Solar thermal converters, 23 10-13 Solar transmittance, for thin films, 23 19 Solatene, 24 558 Solder, 3 53... 

Dawson A., Kamat P.V. (2001) Semiconductor-metal Nanocomposites. Photoinduced Fusion and Photocatalysis of Gold-Capped Ti02 (Ti02/Gold) Nanoparticles, J. Phys. Chem. B. 105(5), 960-966. 

A. Dawson P. V. Kamat, Semiconductor-metal nanocomposites. Photo-induced fusion and photocatalysis of gold-capped Ti02 (Ti02/Au) nanopartides./. Phys. Chem. B 2001, 105, 960-966. 

Several semiconductors possess band gaps suitable to catalyze chemical reactions. Titanium dioxide has become a gold standard semiconductor in the field of photocatalysis. Ti02 is chemically and biologically inert as well as cheap to manufacture and apply. In recent years, applications of NS-Ti02 in environmental remediation have been one of the most active areas in research [30]. 

In contrast to the energetic arguments discussed earlier, superb performance in environmentally relevant photocatalysis (liquid-phase oxidation of phenol and gas-phase NO2 oxidation) has been recently demonstrated by catalysts containing ultrasmall, sub-1 nm gold clusters [197]. Authors reported a remarkable improvement (by a factor of 6) in NO2 conversion when Ti02 was modified with Au clusters. Catalysts were prepared by synthesizing ultrasmall, monodisperse gold clusters... 

Another application of a photochromic reaction involves the reversibile size control of gold aggregates in nanoparticles by using 5-functionalized spiropyran derivatives. In the dark, the merocyanine form associates with each other, which suppresses the thermal rearrangement. Irradiation, on the contraiy, accurately tunes the dimension of the aggregates due to the different electrostatic properties of spiropyran and merocyanine (Fig. 3). In photocatalysis the effect of changing parameters is often limited, because the process of photon absorption photoexcitation of adsorbate -metal bond occur at some distance. It has recently been shown that when sub 5 nm metal particles are used, the hybridized absorbate-metal ions is excited preferentially. This results is an increased proportion of CO oxidation in H2 rich streams (Fig. 4). ... 

Sarina S., Waclawik E. R., and Zhu H. Photocatalysis on supported gold and silver nanoparticles under ultraviolet and visible light irradiation. Green Chemistry. 15 no. 7... 

Keywords photocatalysis, titania, supported catalysts, gold nanoparticles... 

---