Nano structured photocatalysts

Fu J, Ji M,Wang Z, Jin L and An D (2006), A new submerged membrane photocatalysis reactor (SMPR) for fulvic acid removal using a nano-structured photocatalyst , J Hazard Mater, 131,238-242. 

Sun, D., Meng, T.T., Loong, T.H. and Hwa, T.J. (2004) Removal of natural organic matter from water using a nano-structured photocatalyst coupled with filtration membrane. Water Science and Technology, 49,103-10. 

It can be said that not only the above mentioned nano-structure but also other ordinary physical or structural properties measured for photocatalysts have not been proved to be decisive factors for the photocatalytic activities. It is true that photocatalytic activities of photocatalysts of certain components prepared or treated in different ways or under different conditions may be different and this is because physical and structural properties of those photocatalysts differ depending on the preparation/treatment conditions, that is, physical and structural properties must control the photocatalytic activity 49). A problem is we, at least the author, do not know how properties affect photocatalytic activity. A possible reason is that those properties, though we do not know how many properties are required for analysis, are changed at the same time. For example, when titania photocatalysts are prepared by hydrolysis of a titanium compound such as titanium(IV) sulfate or tetra (2-propoxide) followed by calcination in air, higher-temperature... 

The development of improved nano-structured and nano-composite photocatalysts. This is a new active area of research, because the microstructure of... 

Nano-composite photocatalysts, CuOx-TiOa, were synthesized from Cu(OAc)2-intercalated fibrous layered titanates by thermal decomposition in different atmospheres (N2, air, and H2). The structural characterization using XRD, UV-vis, XPS, and SEM implied that the composite of partially reduced CuOx and anatase-t)q3e Ti02 in a waffle-like texture would be a reason for the excellent photocatalytic activity for H2 production from CH3OH/H2O mbttures. 

Preparation of CuO t-1i02 nano-composite photocatalysts from intercalated layer structure... 

The DFT of nano-silicate photocatalyst. Density functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (principally the ground state) of many-body systems, in particular atoms, molecules, and the condensed phases. With this theory, the properties of a many-electron system can be determined by using functionals, i.e. functions of another function, which in this case is the spatially dependent electron density. DFT is among the most popular and versatile methods available in condensed-matter physics, computational physics, and computational chemistry. Therefore, the DFT calculation was employed to analyse the effects of modified silicates using different modified methods. 

Modified of nano-silicate photocatalyst. Although the prepared and natural silicates materials have showed various exceptional performances and also been widely investigated by more and more researchers, there is still a long way to go to realize industrialization application using silicate photocatalysts due to their lower structure stability, lower quantum efficiency as photocatalysts and larger band-gap. 

Attempts to find a suitable catalyst for catalytic applications should take into account several factors. First, nano-structured titania (TiOj) is a well-known photocatalyst. Nano-structured titania could easily improve the photo behavior by modification of the bandgap and introduction of intermediate states. 

Second, a nano-structured metallic catalyst was also applied to photocatalytic application. Ti(IV)/Ce(III)-MCM-41 was synthesized and used as photocatalysts. Ti(IV)/Ce(III)-MCM-41 are active photocatalysts for the oxidative decomposition of 2-propanol into acetone and CO2 under visible-light irradiation, and a synergy effect of Ti(IV) and Ce(III) has been found [97]. 

In this sections, we will present the overview of the natural nano-silicaties as advanced nanoarchitectures currently employed to transform solar into chemical energy. It should be pointed out that this section will emphasize the optimization of silicate-based photocatalysts under sunlight-type excitation operation both under UV and under visible light excitations are considered. In addition, our group s work will be exemplified to discuss the metal oxide-based minerals naturally contain doped transition metal ions isomorphically substituted into the structure that can alter the structural as well as electronic properties. 

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