Enhanced photocatalytic degradation of methylene blue dye using fascily synthesized g-C3N4/CoFe2O4 composite under sun light irradiation

Abstract

In this work, we have reported a successful synthesis of g-C3N4/CoFe2O4 nanocomposite material using a facile co-precipitation method for photocatalytic degradation of methylene blue dye (MB). The crystalline structure, functional groups present, Surface area, Band gap energy and surface charge of the synthesized photocatalysts were investigated by powder x-ray diffraction (PXRD), Fourier transfer Infrared (FTIR) Spectroscopy, BET, UV–Vis spectroscopy and pHpzc techniques respectively. The pXRD result reveals the formation of desired phases of g-C3N4, CoFe2O4, and g-C3N4/CoFe2O4 composite. The energy band gap pure g-C3N4, CoFe2O4, and g-C3N4/CoFe2O4 materials are found to be 2.53, 2.71, and 2.35 eV respectively. The g-C3N4/CoFe2O4 composite achieved the highest surface area of 262.49 m2/g than that of single components. The photocatalytic efficiency of the synthesized materials was investigated by the degradation of MB. Among the synthesized materials, g-C3N4/CoFe2O4 showed highest photocatalytic efficiency of 97.4 % than g-C3N4 and CoFe2O4 which is possibly due to the band gap enhancement and effectively reduces the recombination rate of electron-hole pairs during the photocatalytic reaction. The photocatalytic activities of the g-C3N4/CoFe2O4 composite were also investigated at varying pH of solution, contact time, initial concentration of MB, and photocatalyst dose in order to get the optimized conditions. The reactive species were identified in the catalytic system using ammonium oxalate, ascorbic acid and methanol as hole, superoxide radical and hydroxide radical scavengers respectively. The inhibition appeared from the hole scavenger is the highest and followed by superoxide and hydroxide radicals. From the scavenger experiment, it could be understood that all the reactive species contributed to MB degradation.