Titania and Noble Metals Deposited Titania Catalysts in the Photodegradation of Tartazine

Abstract

Nanoparticles of TiO 2 were synthesised by sol-gel technique and photo deposition of about 1% noble metal (M/TiO 2 , M = Ag, Au, and Pt) on TiO 2 was carried out. The catalysts were characterised by XRD, TEM, BET, FT-IR, and UV-Visible spectroscopy. Using commercial TiO 2 (P-25 Degussa), the conditions such as dye concentration, catalyst weight and pH were optimized for complete decolourisation of textile dye tartazine (TAZ) under UV and visible irradiations. Among the catalysts tested, the synthesised TiO 2 showed better photocatalytic activity than TiO 2 (P-25 Degussa). Whereas, M/TiO 2 catalysts showed remarkable photocatalytic activity towards the decolourisation of TAZ even under visible irradiation. This enhanced activity of M/TiO 2 catalyst may be attributed to the trapping of conduction band electrons by noble metals.

A review on plasmonic metal⿿TiO2 composite for generation, trapping, storing and dynamic vectorial transfer of photogenerated electrons across the Schottky junction in a photocatalytic system

“…Further higher Au 3+ sites serve as recombination centers [92]. Au/TiO 2 showed enhanced activity compared to Ag/TiO 2 and Pt/TiO 2 for the degradation of tartrazine [93]. It has been confirmed by several studies that the catalytic properties of metal/semiconductor heterostructure photocatalyst depends significantly on the size of deposited metal particles, the interaction between metal and TiO 2 and on the active sites on the nanostructure.…”

A review of TiO2 nanoparticles

“…Noble metals including Pt, Ag, Au, Pd, Ni, Rh and Cu have been reported to be very effective at enhancing photocatalysis by TiO 2 [87][88][89][90][91][92]. Because the Fermi levels of these noble metals are lower than that of TiO 2 , photoexcited electrons can be transferred from the conduction band of TiO 2 to metal particles deposited on the surface of TiO 2 , while photogenerated holes in the valence band remain on TiO 2 .…”

“…Rupa et al [87] synthesized TiO 2 nanoparticles by the sol-gel technique and doped the nanoparticles with about 1% noble metal (M/TiO 2 , M = Ag, Au, and Pt) through photodeposition. M/TiO 2 catalysts showed remarkable photocatalytic activity towards the decolorization of tartrazine even under visible irradiation.…”

Magnetic Nano-photocatalysts: Preparation, Structure, and Application

“…Another example is that sugar can be decomposed into carbon dioxide and hydrogen gas using titanium dioxide powders loaded with RuO 2 (wt10%) and Pt (wt5%) particles under irradiation (Kawai and Sakata 1980 ) . Moreover, the photocatalysts loaded with noble metal particles in the suspension aqueous solution were broadly utilized to degrade the refractory organic pollutants (Serpone and Pelizzetti 1989 ;Kamat 1993 ;Pelizzetti et al 1993 ;Rajeshwar 1995 ;Hoffmann et al 1995 ;Halmann 1996 ;Fujishima et al 1999 ;Kozlova and Vorontsov 2006 ;Ren et al 2009 ;Iliev et al 2010 ;Rupa et al 2009 ) in the presence of oxygen, and the catalytic activities The photo-generated electrons fl ow into the inert platinum electrode to reduce hydrogen ions into hydrogen gas and the photo-generated holes leave to oxidize the water to release oxygen gas upon irradiation Fig. 4.2 Semiconductor photocatalyst suspended in aqueous solution.…”