Efficient Degradation of Methylene Blue Dye Over Highly Reactive Cu Doped Strontium Titanate (SrTiO_3) Nanoparticles Photocatalyst Under Visible Light

摘要

Visible light induced photocatalysts of Cu doped SrTiO_3 (Cu/SrTiO_3) nanoparticles with the size ～60-75 nm were prepared via facile sol-gel method. The morphological, optical, crystalline properties and compositions of synthesized Cu/SrTiO_3 nanoparticles were thoroughly characterized by field emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD), ultra violet - visible spectroscopy (UV-Vis) and energy dispersive X-ray (EDX). A significant red shift in the UV-diffused reflectance spectrum was observed and the absorption edge shifted to visible region by the Cu doping. Surprisingly, the band gap of SrTiO_3 was changed from 3.2 eV drop to 2.96 eV. The photocatalytic activity of the synthesized Cu/SrTiO_3 nanoparticles was demonstrated for the degradation of Methylene Blue dye under visible light irradiation. The formation of new acceptor region in Cu/SrTiO_3 was responsible for high photocatalytic activity of Cu/SrTiO_3 nanoparticles. The results showed that the Methylene Blue dye was degraded by ～66% within time span of 2 h over the Cu/SrTiO_3 nanoparticles. This dye degradation reaction followed the Langmuir-Hinshelwood kinetics and also exhibited first order reaction rate. The calculated rate constant for the degradation reaction following first order kinetics was k = 0.0016 min~(-1).