Self-organized graphene oxide and TiO2 nanoparticles incorporated alginate/carboxymethyl cellulose nanocomposites with efficient photocatalytic activity under direct sunlight

Novel nanocomposites of Sr2+ ion crosslinked alginate/carboxymethyl cellulose (Alg/CMC) with TiO2 nanoparticles (TiO2-NPs) and graphene oxide (GO) incorporation was synthesized using simple dissipative convective route followed by freeze drying processes. As-synthesized nanocomposites were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV- visible-diffuse reflectance spectroscopy (UV-vis-DRS), surface area study, Raman spectroscopy, scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDAX) and transmission electron microscopy (TEM) analysis, respectively. The results revealed that GO and TiO2-NPs were successfully incorporated into alginate/CMC matrix and visible light response of TiO2 was significantly improved. Photocatalytic performance of nanocomposites was evaluated by degradation of congo red (CR) dye under direct sunlight irradiation. The degradation results disclosed that GO and TiO2-NPs incorporated Sr/alginate/CMC nanocomposites (Sr/Alg/CMC/GO/TiO2) can competently degrade the tested CR dye molecules and showed greater degradation efficiency (98%) than the Sr/Alg/CMC/TiO2 (70%), Sr/Alg/CMC (60%) and bare TiO2 (62%) photocatalyst, respectively. Moreover, recyclability study of Sr/Alg/CMC/GO/TiO2 nanocomposite demonstrated that it was highly stable under reaction condition and retained its degradation efficiency up to seven consecutive cycles of degradation reaction. Our results suggested that Sr/Alg/CMC/GO/TiO2 is an efficient visible light responsive photocatalyst for degradation of dye molecules in the presence of direct sunlight irradiation using present reaction conditions.