Photocatalytic reduction, visible-light

The primary target of studies on photocatalytic semiconductor suspensions has been water cleavage by visible light. Suspension-based photocatalytic processes are also useful for the removal of inorganic (metal ions) and organic pollutants, the reduction of CO2, the photodestruction of bacteria and viruses, and various organic reactions an example is the use of Pt-loaded CdS for the photocatalytic racemization of L-lysine [210]. 

Sterilisation of blood products and other organ transplant tissues opens another area for photodynamic effect applications. Photodynamic activity of some inorganic sensitizers together with their photocatalytic activity can be very useful in water, air, and surface detoxification (see Chapter 21). APDT can be a new approach for safe food. The reduction of several Gram-positive bacteria and yeasts has been observed in tests with visible light and haematoporphyrin or chlorophylls (natural constituents of food) as photosensitizers [54],... 

Photocatalytic CO2 reduction of a supramolecule with a Zn porphyrin unit, which is a redox photosensitizer that can absorb even wider ranges of visible light, connected to a rhenium complex (ZnTMP-ReCl) was considered (101,102). In this system, ultrafast (l.SxlO s ) electron transfer from the S2 excited state of the ZnTMP unit to the rhenimn imit was observed. Reduction of CO2 proceeded with generation of the OER species of the rhenium unit by the reduction of this intramolecular charge-transfer state by TEA. 

Recently we have reported on the photocatalytic reduction of CO2 under visible-light irradiation using CdS-DMF at a high quantum yield of 0.098 at k=405 nm. [4,5] The induction period observed in the formation of CO suggests the importance of the surface conditions for the photocatalysis. 

Wu T, Liu S, Luo Y, Lu W, Wang L, Sun X (2011) Surface plasmon resonance-induced visible light photocatalytic reduction of graphene oxide using Ag nanoparticles as a plasmonic photocatalyst. Nanoscale 3 2142-2144... 

The CO2 adsorption and the concurrent reaction with the electrons highly depends on the nature of the material surfaces. Not all the semiconductors have the similar surface arrangement, therefore, the reaction pathway and the interaction of CO2 moiety with surfaces varies according to the materials used. The product and yield vary within the titanium dioxide compounds itself [124]. Since the CO2 reduction doesn t only depend on the visible light activity of the photocatalytic material, but also many other fac-... 

Tang, C. Hou, W. Liu, E. Hu, X. Fan, J. CeF3/Ti02 composite as a novel visible-light-driven photocatalyst based on upconversion emission and its application for photocatalytic reduction of C02. J. 

The type and density of surface states of NS-Ti02 are affected by the synthesis process. For instance, a soft mechanical treatment of TiOi nanopowder was found to reduce its photocatalytic activity in the reduction of Cr(VI) [61]. On the other hand, treatment in either H2 or N2 plasma was found to enhance the activity within the visible-light range for certain reactions [62]. The interplay between processing conditions and photocatalytic activity remains largely a state-of-the-art and is beyond prediction at this point. Ti02 has typically been calcined or... 

Monoclinic crystals of BiV04 photocatalyzed CO2 reduction to C2H5OH in aqueous solution without a sacrificial electron drmor [84]. BiV04 can act as visible-light responsive photocatalyst, and photocatalytic activity improved under intense light irradiation. The maximum TF reached ca. 1.5 nunol (g cat.) h. The authors presumed that the intense irradiation enhances the production of reactirm intermediates. 

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