Photocatalysis catalyzed photolysis

UV peroxide process Ozonolysis Peroxon process Fe3+-catalyzed photolysis Photoassisted Fenton process Photocatalysis... 

In catalyzed photolysis either the catalyst molecule (Fig. 5-11, situation B) or the substrate molecule (Fig. 5-11, situation C), or both, are in an electronically excited state during the catalytic step. The electronically excited catalyst molecule is produced via photon absorption by a nominal catalyst (Fig. 5-11, situation B). The reaction of substrate to product is catalytic with, respect to the concentration of the electronically excited catalyst species. It is non-catalytic in photons and therefore, continuous irradiation is required to maintain the catalytic cycle. The quantum yield of product formation Product is equal to or less than unity. Titanium dioxide photocatalysis is the most widely applied example of this type, with Ti02 representing the nominal catalyst that must be electronically excited by photon absorption with formation of the electron hole pair Ti02 (hvb + cb), being the active catalytic species (cf Fig. 3-17 and Fig. 5-9, reaction 1). The oxidation of substrates by the combination of UV/VIS radiation and an appropriate photocatalyst is often called photocatalytic oxidation (PCO). 

Photocatalysis includes various reactivity types which may be divided into two categories depending on the role of light on (i) photogenerated catalysis consisting of reactions catalytic in photons and (ii) catalyzed photolysis, in which processes are non-catalytic in photons (Fig. 1). 

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