Studies on photocatalytic activity of the synthesised TiO2 and Ag/TiO2 photocatalysts under UV and sunlight irradiations

Abstract

Photocatalytic decolorisation and degradation of Reactive Red 120 (RR 120) has been investigated under UV (365 nm) and solar light as radiation sources using synthesised nano titania catalyst prepared via sol-gel method. The study encompassed calcination of synthesised titania catalyst at a range of temperature up to 1,000°C. The effects of calcination temperature on titania catalyst have been evaluated on the decolorisation of RR 120. The analysis revealed complete decolorisation of dye solution in 100 min under UV light with the TiO2 catalyst calcined at 200°C. Only a maximum of 47% dye decolorisation was achieved under sunlight in 4 h with no improvement even after prolonged irradiation. In an endeavour to improve the catalytic activity, bare titania was modified with silver metal and a comprehensive study on the characteristics of silver modified catalyst was made. The result was an enhancement of the rate of decolorisation of dye under both UV and solar light sources. All the catalysts were characterised by XRD and BET analyses. Optimisation of the degradation of RR 120 has been carried out using the unmodified catalyst by varying the amount of catalyst, substrate concentration, pH of dye solution. Effects of addition of small amounts of various oxidants such as H2O2, KBrO3 and (NH4)2S2O8 have also been studied. Pseudo first order kinetics was observed in the photocatalytic decolorisation of dye. The mineralisation of RR 120 was monitored by TOC analysis.

Ag‐Enhanced TiO2–x/C Composites with Metal‐Organic Frameworks as Precursors for Photodegradation of Methyl Blue

“…Under UV‐light irradiation, Ag/TiO 2– x /C composites obtain energy to generate electron‐hole (e – ‐h + ) pairs. Ag particles can also reduce the recombination probability of the photogenerated carriers by rapidly capturing and releasing photogenerated carriers . Then holes react with H 2 O to produce • OH radicals, electrons react with O 2 adsorbed on the surface of the catalyst to produce superoxide • O 2 – radicals, and the resulting • O 2 – and • OH radicals are highly reactive , .…”

Fabrication of M@CuxO/ZnO (M= Ag, Au) Heterostructured Nanocomposite with Enhanced Photocatalytic Performance under Sunlight

“…Therefore, longer wavelengths, even up to the near-infrared (NIR) band of the solar spectrum, remain vacant. The localized SPR outcome of metal nanoparticles (MNPs) brings a huge convenience for higher plasmonic performance as a photocatalyst. − Among metal NPs, Ag and Au have the strapping SPR consequence, and that can be absorbing lower energy. , Also, the peculiar reactivity and functionality as electrons sink of MNPs supply developing charge transport duration and material performance particularly for photocatalysis . Based on a similar consideration, the activity of Cu 2 O/ZnO establishing a photocatalyst can be further enhanced by the loading of MNPs.…”

“…13−15 Among metal NPs, Ag and Au have the strapping SPR consequence, and that can be absorbing lower energy. 16,17 Also, the peculiar reactivity and functionality as electrons sink of MNPs supply developing charge transport duration and material performance particularly for photocatalysis. 18 Based on a similar consideration, the activity of Cu 2 O/ZnO establishing a photocatalyst can be further enhanced by the loading of MNPs.…”

Enhanced photocatalytic performance of sandwiched ZnO@Ag@Cu2O nanorod films: the distinct role of Ag NPs in the visible light and UV region

“…Considering the visible-light response and energy band arrangement with ZnO or TiO 2 , Cu 2 O is an appropriate sensitization material. For metalsemiconductor (M-S) composite photocatalysts, the metallic component could also enhance the light absorption of the semiconductors through a localized surface plasmon resonance (LSPR) effect [7,8]. Meanwhile, the built-in Schottky barrier can also efficiently inhibit the carrier recombination [9][10][11][12][13][14].…”

“…Among the plasmonic nanoparticles (NPs), Ag NPs have the strongest LSPR effect, and the LSPR peak can be tuned to a longer visible wavelength [7,8]. However, their oxidation character puts forward a more serious requirement on the loading form [17][18][19].…”