Titanium photocatalyst

Colmenares, J.C., Magdziarz, A., Bielejewska, A., 2011. High-value chemicals obtained from selective photooxidation of glucose in the presence of nanostructured titanium photocatalysts. Bioresource Technology 102 (24),... 

Heterogeneous Photocatalysis. Heterogeneous photocatalysis is a technology based on the irradiation of a semiconductor (SC) photocatalyst, for example, titanium dioxide [13463-67-7] Ti02, zinc oxide [1314-13-2] ZnO, or cadmium sulfide [1306-23-6] CdS. Semiconductor materials have electrical conductivity properties between those of metals and insulators, and have narrow energy gaps (band gap) between the filled valence band and the conduction band (see Electronic materials Semiconductors). 

Tioxide process. This process is similar to that used to produce fumed silicas. Ultra-low particle size titanium dioxide (15-35 nm) is obtained for use as photocatalyst or UV absorber (for instance in sun protective creams). 

Fig.3 shows an effect of titanium dioxide loading on the decomposition of ethylene over a 20mesh wire-net photocatalyst. The decomposition rate increased in proportion to the amount of titanium dioxide loaded The specific initial rate (ro=(-dc/dt)t=o) was (1.8 0.2)x 10 ppm s g-catalysf. ... 

The photocatalytic activity of 20mesh wire-net photocatalyst was observed to be nearly equal to that of 350mesh one under the same amount of titanium dioxide loading (1.88 g). 

Recently, it is reported that Xi02 particles with metal deposition on the surface is more active than pure Ti02 for photocatalytic reactions in aqueous solution because the deposited metal provides reduction sites which in turn increase the efficiency of the transport of photogenerated electrons (e ) in the conduction band to the external sjistem, and decrease the recombination with positive hole (h ) in the balance band of Xi02, i.e., less defects acting as the recombination center[l,2,3]. Xhe catalytic converter contains precious metals, mainly platinum less than 1 wt%, partially, Pd, Re, Rh, etc. on cordierite supporter. Xhus, in this study, solutions leached out from wasted catalytic converter of automobile were used for precious metallization source of the catalyst. Xhe XiOa were prepared with two different methods i.e., hydrothermal method and a sol-gel method. Xhe prepared titanium oxide and commercial P-25 catalyst (Deagussa) were metallized with leached solution from wasted catalytic converter or pure H2PtCl6 solution for modification of photocatalysts. Xhey were characterized by UV-DRS, BEX surface area analyzer, and XRD[4]. 

Ward MD, White JR, Bard AJ (1983) Electrochemical investigation of the energetics of particulate titanium dioxide photocatalysts. The methyl viologen-acetate system. J Am Chem Soc 105 27-31... 

Ranjit KT, Willner I, Bossmann SH, Braun AM (2001) Lanthanide oxide doped titanium dioxide photocatalysts Novel photocatalysts for the enhanced degradation of p-chlorophe-noxyacetic acid. Environ Sci Technol 35 1544—1549... 

Uzunova-Bujnova M, Todorovska R, Dimitrov D, Todorovsky D (2008) Lanthanide-doped titanium dioxide layers as photocatalysts. Appl Surfac Sci 254 7296-7302... 

Shiraishi, Y. and Hirai, T. (2008) Selective organic transformations on titanium oxide-based photocatalysts. Journal of Photochemistry and Photobiology C Photochemistry Reviews, 9 (4), 157-170. 

Awazu, K., Fujimaki, M., Rockstuhl, C., Tominaga, J., Murakami, H., Ohki, Y., Yoshida, N., and Watanabe, T. (2008) A plasmonic photocatalyst consisting of silver nanoparticles embedded in titanium dioxide. Journal of the American Chemical Society, 130 (5), 1676-1680. 

Martinez-Ferrero, E., Sakatani, Y., Boissire, C., Grosso, D., Fuertes, A., Fraxedas, J., and Sanchez, C. (2007) Nanostructured titanium oxynitride porous thin films as efficient visible-active photocatalysts. Advanced Functional Materials, 17 (16), 3348—3354. 

Wu, P., Xie, R., Imlay, J.A., and Shang, J.K. (2009) Visible-light-induced photocatalytic inactivation of bacteria by composite photocatalysts of palladium oxide and nitrogen-doped titanium oxide. Applied Catalysis B Environmental,... 

Kitano, M., Tsujimaru, K., and Anpo, M. (2008) Hydrogen production using highly active titanium oxide-based photocatalysts. Topics in Catalysis, 49 (1-2), 4-17. 

Ohtani, B., Iwai, K., Kominami, H., Matsuura, T., Kera, Y., and Nishimoto, S. (1995) Titanium(IV) oxide photocatalyst of ultra-high activity for selective N-cyclization of an amino acid in aqueous suspensions. Chemical Physics Letters, 242 (3), 315-319. 

Nanomaterials can also be tuned for specific purposes through doping. Specifically, the effect of the presence of manganese oxides on photocatalysis involving primarily titanium dioxide will be considered in this section. Titanium dioxide is a well-known photocatalyst and will be considered separately. K-OMS-2, which has a cryptomelane structure, is illustrated in Figure 8.4. Not all the literature discussed in this section, however, involves OMS tunnel structure materials. For example, amorphous manganese oxide (AMO) is also discussed as a photocatalyst. Manganite (MnOOH) is also included in battery applications. 

Han, F., Kambala, V.S.R., Srinivasan, M., Rajarathnam, D. and Naidu, R. (2009) Tailored titanium dioxide photocatalysts for the degradation of organic dyes in wastewater treatment a review. Applied Catalysis A General, 359, 25-40. 

---