title: A novel bio-degradable polymer stabilized Ag/TiO2 nanocomposites and their catalytic activity on reduction of methylene blue under natural sun light.
abstract: In the present work we defined a novel method of TiO2 doped silver nanocomposite synthesis and stabilization using bio-degradable polymers viz., chitosan (Cts) and polyethylene glycol (PEG). These polymers are used as reducing agents. The instant formation of AgNPs was analyzed by visual observation and UV-visible spectrophotometer. TiO2 nanoparticles doped at different concentrations viz., 0.03, 0.06 and 0.09mM on PEG/Cts stabilized silver (0.04wt%) were successfully synthesized. This study presents a simple route for the in situ synthesis of both metal and polymer confined within the nanomaterial, producing ternary hybrid inorganic-organic nanomaterials. The results reveal that they have higher photocatalytic efficiencies under natural sun light. The synthesized TiO2 doped Ag nanocomposites (NCs) were characterized by SEM/EDS, TEM, XRD, FTIR and DLS with zeta potential. The stability of Ag/TiO2 nanocomposite is due to the high negative values of zeta potential and capping of constituents present in the biodegradable polymer which is evident from zeta potential and FT-IR studies. The XRD and EDS pattern of synthesized Ag/TiO2 NCs showed their crystalline structure, with face centered cubic geometry oriented in (111) plane. AFM and DLS studies revealed that the diameter of stable Ag/TiO2 NCs was approximately 35nm. Moreover the catalytic activity of synthesize Ag/TiO2 NCs in the reduction of methylene blue was studied by UV-visible spectrophotometer. The synthesized Ag/TiO2 NCs are observed to have a good catalytic activity on the reduction of methylene blue by bio-degradable which is confirmed by the decrease in absorbance maximum value of methylene blue with respect to time using UV-vis spectrophotometer. The significant enhancement in the photocatalytic activity of Ag/TiO2 nanocomposites under sun light irradiation can be ascribed to the effect of noble metal Ag by acting as electron traps in TiO2 band gap.
authors.affiliation: Department of Physics, Annamalai University, Annamalai Nagar 608002, Tamil Nadu, India. Electronic address: geeramphyau@gmail.com.
authors.forename: D
authors.initials: D
authors.lastname: Geetha
authors.affiliation: Department of Physics, Annamalai University, Annamalai Nagar 608002, Tamil Nadu, India.
authors.forename: S
authors.initials: S
authors.lastname: Kavitha
authors.affiliation: Physics Wing DDE, Annamalai University, Annamalai Nagar 608002, Tamil Nadu, India.
authors.forename: P S
authors.initials: PS
authors.lastname: Ramesh
mesh_terms: D063566:Biodegradable Plastics / Q000737:chemistry*; D002384:Catalysis; D048271:Chitosan / Q000737:chemistry; D004785:Environmental Pollutants / Q000737:chemistry / Q000302:isolation & purification*; D008751:Methylene Blue / Q000737:chemistry / Q000302:isolation & purification*; D053761:Nanocomposites / Q000737:chemistry*; D055668:Photochemical Processes; D011092:Polyethylene Glycols / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013472:Sunlight; D014025:Titanium / Q000737:chemistry*
chemical_list: D063566:Biodegradable Plastics; D004785:Environmental Pollutants; C009495:titanium dioxide; D012834:Silver; D011092:Polyethylene Glycols; D048271:Chitosan; D014025:Titanium; D008751:Methylene Blue
keywords: Photocatalytic activity; Polymer blend as reducer; Silver/TiO(2) nanocomposite