Abstract
The Graphene Oxide (GO) and GO-Zinc Oxide (GO-ZnO) nanocomposite were prepared using simplified techniques with modified Hummer’s and solvothermal methods for photocatalytic application. In a comparative study, the optimized geometries, binding energies, electronic properties, non-linear optical properties and density of states of GO-ZnO were calculated using density functional theory (DFT) calculations with B3LYP method at 6-31G (d,p) and LanL2DZ basis sets to examine the binding site of a methylene blue (MB) dye systematically. The result of Natural bond orbital (NBO) analysis revealed the effective charge transfer and also explained the mechanism and efficiency of the photocatalytic activity of GO-ZnO. Density of states supported the strong interaction of MB with the GO-ZnO leading to the degradation of the MB dye. The attained theoretical results depict the existence of n → σ*, n → n* and σ → σ* interactions, improved charge transfer, reduced band gap which establish the use of GO-ZnO in the visible light photocatalytic performance. Characterization methods such as XRD, FTIR and UV were carried out to support our theoretical results. The XRD results confirmed the particle size of 21 nm with inter layer spacing of 0.87 nm. FTIR spectroscopy indicated the characteristic bands related to the elements in GO-ZnO. The higher electrical conductivity is studied using UV-Vis spectral analysis. The calculated results show good agreements with experimental observations reveal that the GO-ZnO has good photocatalytic behavior.
Kinetics and Adsorption Isotherm Studies of Methylene Blue Photodegradation Under UV Irradiation Using reduced Graphene Oxide- TiO2 Nanocomposite in Different Wastewaters Effluents.