Outstanding photocatalytic activity of CoFe2O4 /rGO nanocomposite in degradation of organic dyes

In this research, the efficiency of organic dyes degradation over cobalt ferrite, CoFe2O4, nanoparticles loaded on the reduced graphene oxide (rGO) photocatalyst was investigated. The effect of Triton X-100 (TX-100) surfactant usage in synthesis process was also studied. The addition of rGO to the CoFe2O4 and use of TX-100 led to a decrease in crystallite size to 14 nm, increase of specific surface area to 116 m2/g and decrease of band gap energy to 1.75 eV. Vibrating sample magnetometer (VSM) study displayed the reduction of magnetic properties in CoFe2O4/rGO nanocomposite, while the coercivity increased sharply when the TX-100 used as a surfactant. Reduction in Photoluminescence (PL) peaks, increasing average lifetime (~1.92 ns) obtained from time-resolved fluorescence (TRF), increasing the photocurrent value and the reduction of charge transfer resistance confirmed that the CoFe2O4/rGO nanocomposite with TX-100 surfactant have a better charge transfer efficiency comparing with other samples. 5 ppm of initial methylene blue (MB) concentration, and 0.5 g/L of catalyst dosage was determined as the optimal photocatalyst operating setting after 180 min of visible light irradiation. The nanocomposite sample showed the higher degradation efficiency for MB than those of methyl orange (MO) and Rhodamine B (RhB) dyes under visible light illumination. Also, the kinetics and mechanism of photocatalytic degradation process were explained in detail. The magnetically recyclable nanocomposite exhibited high reusability and stability during the cyclic photocatalytic degradation.