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APLICATII FOTOCATALITICE ALE COMPOZITELOR NANOSTRUCTURATE PE BAZA DE TiO 2

APLICATII FOTOCATALITICE ALE COMPOZITELOR NANOSTRUCTURATE PE BAZA DE TiO 2. 1. Imbunatatirea procesului de oxidare fotocatalitica a acidului oxalic utilizand fotocatalizator WO 3 /TiO 2 modificat cu nanoparticule de Au, iradiat UV, respectiv Vis.

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APLICATII FOTOCATALITICE ALE COMPOZITELOR NANOSTRUCTURATE PE BAZA DE TiO 2

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  1. APLICATII FOTOCATALITICE ALE COMPOZITELOR NANOSTRUCTURATE PE BAZA DE TiO2 1. Imbunatatirea procesului de oxidare fotocatalitica a acidului oxalic utilizand fotocatalizator WO3/TiO2 modificat cu nanoparticule de Au, iradiat UV, respectiv Vis • - WO3 is a semiconductor photocatalyst with a band gap of 2.8 eV, which is activated by visible light illumination. • The basic disadvantage of WO3 as a photocatalyst is its low photonic efficiency. • the activity of WO3/TiO2 photocatalysts, under UV light irradiation, is highest at an optimum WO3 content in the composite material of about 3–4 wt%. • The promoting effect of noble metals (in particular gold) on the WO3/TiO2 system efficiency, has received little attention so far in the literature

  2. Total degree of mineralization of oxalic acid (1.8×10−2 mol/L) at pH 4 by irradiation with: • UV light: a: absence of catalyst; b: WO3; c: Au/WO3; d: TiO2; e: WO3/TiO2; f: Au/TiO2; g: Au/WO3/TiO2; • visible light: a: TiO2; b: Au/TiO2; c: WO3; d: WO3/TiO2; e: Au/WO3; f: Au/WO3/TiO2.

  3. Dependence of the apparent rate constants kapp of photocatalytic degradation of oxalic acid on the type of irradiation: gri– UV light; negru– visible light; pestrit– combined UV–visible light.

  4. Schematic representation of charge carrier separation in the photoexcited Au/WO3/TiO2 photocatalyst

  5. 2. Fotodegradarea fenolului utilizand ca fotocatalizator compozit ZrO2 - TiO2 Phenol is an extremely toxic organic compound which is highly soluble in water and a major pollutant. It is used in the manufacture of polymeric resins, herbicides and fungicides, oil refining, paper mills and in the pharmaceutical industry. Phenol has also become one of the most widely used petrochemical products and demand is increasing and global production of phenol reached 8 million tonnes in 2009. Since 2001 there has been a 45% increase in demand for the phenol derivative bisphenol A for the production of polycarbonate resins used in the manufacture of CDs, CD-ROMs and DVDs. 42% of the global production of phenol is for bisphenol A synthesis, followed by phenolic formaldehyde resins at 28% used in the production of circuit boards, coatings and adhesives. Phenol is a protoplasmic poison and poses a major concern to both drinking water and the aquatic environment. It is hazardous to humans as it is corrosive and cellular uptake is rapid after exposure and mainly affects the liver and kidneys but can also affect the respiratory, nervous and cardiovascular systems.

  6. Mecanismul fotodescompunerii fenolului pe TiO2 Profilele de difractie cu raze X ale TiO2 tratat termic la diferite temp.

  7. Influenta continutului de ZrO2 asupra gradului de cristalizare a TiO2

  8. The incorporation of zirconia helped stabilize the anatase phase up to higher degrees. This allowed for an ideal anatase to rutile ratio and larger surface area. TiO2 doped with 1% (molar metal content) of zirconia (Zr 100/1) at pH 5 proved to be the best catalyst removing 0.0249 mg g−1 h−1W−1.

  9. r – viteza de reactie la ech. kr – constanta de viteza KC0 – constanta de echilibru

  10. 3. Activitatea fotocatalitica a nanotuburilor de TiO2 dopate cu azot The anatase TiO2 material cannot efficiently utilize visible light ( > 380 nm) of the solar energy because of its comparably large band gap. To overcome this problem, considerable efforts have been taken to narrow the band gap. Doping with nonmetal anions have been explored in an effort to increase the visible light absorption or suppress the recombination of photogenerated carries. • The common approaches to form N-doped TiO2 photocatalyst include: • sputtering of TiO2 targets in N2 mixture gas, • annealing TiO2 or Ti-compounds under ammonia gas, • ion implantation and thermal treatment and hydrolysis of N-containing solutions.

  11. SEM top-view images of (a) TiO2 nanotube array annealed at 450 ◦C, N-doped TiO2 nanotube arrays annealed at various temperatures (b) 450 ◦C, (c) 600 ◦C, and (d) 700 ◦C.

  12. Profilele variatiei concentratiei de metilorange in urma fotodescompunerii utilizand (a) lampa de Hg, (b) lampa cu W

  13. Profile HPLC ale Metil Orange in urma fotodegradarii

  14. Final:

  15. 3. Activitatea fotocatalitica a compozitelor Mn/TiO2 depuse pe silicagel Reactiile fotocatalitice

  16. 4. Oxidarea selectiva a alcoolului benzilic la benzaldehida pe sistemul TiO2/Cu(II)/UV

  17. 5. Nanoparticule de Ag depuse pe nanotuburi de TiO2 – fotocatalizatori in procesul de oxidare a etanolului Imagini SEM pentru nanotuburi Ag / TiO2 tratate termic la 923 K.

  18. Imagine TEM

  19. Reactiile fotocatalitice

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