Visible light-induced photocatalysis

Kanemoto, M. Ishihara, K. Wada, Y. Sakata, T. Mori, H. Yanagida, S. Semiconductor photocatalysis. Part 13. Visible-light induced effective photoreduction of C02 to CO catalyzed by colloidal CdS microcrystallites, Chem. Lett. 1992, 6. 

This review has been written in order to clarify fundamental aspects of photocatalysis, an important subject in inorganic and material chemistry, not to present a list of studies on photocatalysis reported so far, since it seems rather difficult to make a complete review by introducing all or a large part of the reported studies on photocatalysis of relatively long history. This review is based on the author s experience in studies on photocatalysis and topics are limited to so-called semiconductor photocatalysis definition and examples of photocatalysis, its principle and kinetics, visible light-induced photocatalysis, and design of active photocatalysts are discussed in detail. 

Visible-light induced photoreduction of CO2 proceeds on CdS nanocrystallites when they are stabilized by specific solvation of organic solvent molecules like DMF. Formation of sulfur vacancies as CO2 adsorptive sites and sustained quantization effect of CdS nanocrystallites are requisites for their effective photocatalysis. Adsorptive activation of both CO2 molecules and appropriate organic molecules leads to photofixation of CO2 to the organic molecules on CdS nanocrystallites (CdS-DMF). 

Chen, H.-W., Y. Ku, and Y.-L. Kuo, Effect of Pt/TiOj characteristics on temporal behavior of o-cresol decomposition by visible light-induced photocatalysis. 

Recently, scientists have extensively utilized the abundantly available solar light to generate free radicals for further use in the functionalization of inert C-H bonds (see Scheme 2.1) [8,9]. However, neither visible-light-induced photocatalysis nor the free carbenes and nitrenes approach allows greater control selectivity and yield of the C-H functionahzation reactions. 

Scheme 13.1 Mechanism profile of visible-light-induced photocatalysis.

Since 2008, visible-light-induced photocatalysis has experienced vigorous development in hopes of its utilization as a green chemistry technique. Through... 

Such photocatalysis can also be induced by slight ultraviolet radiation due to fluorescent lights, etc. In 2001, the nitrogen-doped TiO photocatalyst to enable a photocatalysis under visible light was developed [2], and has attracted much attention since then. More recently C-doped photocatalysts have been developed [6]. Construction materials with TiO photocatalyst develop the major performance or functions as shown in Fig. 1.3 [16, p. 21 24, p. 12], based on both effects of strong decomposition power and high water-wettability. 

---