Abstract:
Photocatalysis based on semiconductors is a likely approach to overcome many pollution
problems and eliminate toxic organic compounds from waste-water. TiO2 due to its unique
properties is considered as a promising semiconductor. Despite its intriguing properties,
TiO2 is unable to absorb visible part of light due to which the overall photocatalytic
activity is affected. In this thesis, TiO2 nanoparticles were synthesized in its pure anatase
phase using sol-gel method. To reduce the band gap, N doped TiO2 and N and Cu codoped
TiO2 nanoparticles with varying concentrations of Cu (0.1%, 0.5%, 1%, 2%, 3 wt
%)were synthesized to obtain both non-metal and metal dopant properties. Tetra titanium
iso-propoxide, urea and Cu (NO3)2.3H2O were used as precursors for TiO2 nanoparticles
and N and Cu doping, respectively. The prepared catalysts were characterized using XRD,
SEM, EDS, FT-IR and UV/Vis-DRS. Both crystallite size and particle size for doped
catalysts were reduced as compared to pure TiO2 nanoparticles. The degradation studies
for the prepared photocatalysts were performed on methyl orange under visible light using
LEDs. The kinetic studies exhibited that photocatalytic performance of 2% Cu/N co-doped
TiO2 was best amongst all prepared catalysts with an efficiency of 93%. To further
improve the efficiency, nanocomposites of the as-prepared best catalyst and graphene
oxide were prepared. GO nanosheets were prepared using Hummers’ method by using
graphite flakes as a precursor and KMnO4 as an oxidizing agent. Incorporation of 2% Cu/N
co-doped TiO2 nanoparticles on GO sheets was done by using hydrothermal method and
different percentages of GO: TiO2 (0.5:1, 1:1 and 2:1) were prepared to study the effect of
amount of GO. Degradation studies were performed on methyl orange again and the
kinetic studies showed that the efficiency was increased to 96%.
