Surfactant assisted hydrothermal synthesis of MgO/g-C3N4 heterojunction nanocomposite for enhanced solar photocatalysis and antimicrobial activities

In this work, Multilayer coral reef like MgO/g-C3N4 nanocomposite was synthesized by surfactant-assisted hydrothermal method. The crystal structure, functional groups and surface area of MgO/g-C3N4 nanocomposite was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and Brunauer-Emmett-Teller (BET) studies. Further, high-resolution scanning electron microscopy (HRSEM) and high-resolution transmission electron microscopy (HRTEM) were used for analyzing coral reef-like morphology of MgO/g-C3N4 nanocomposite. Chemical constituents of synthesized nanocomposites were confirmed by energy dispersive X-ray (EDX) spectroscopy. Optical studies of MgO/g-C3N4 nanocomposites confirm the reduction of photogenerated electron-hole recombination rate. The synthesized MgO/g-C3N4 nanocomposite exhibits high photocatalytic performance in comparison to pure MgO and g-C3N4 by degradation of Malachite Green under irradiation of sunlight. The MgO/g-C3N4 nanocomposite shows good stability along with high degradation efficiency after five runs. The highest rate constant of 0.1079 min−1 was obtained for Malachite Green dye removal by MgO/g-C3N4 catalyst which is almost 5.3 and 13.6 times superior in comparison to MgO (0.0207 min−1) and g-C3N4 (0.00789 min−1) , respectively. Additionally, the antibacterial activity of the MgO/g-C3N4 nanocomposite was investigated for Gram-positive and Gram-negative bacterium such as S. aureus, B. subtilis, and E. coli, P. aeruginosa, respectively. The zone of inhibition is observed in the range 6 mm to 7 mm and increased with increasing the concentration of the MgO/g-C3N4 nanocomposite due to the formation of reactive oxygen species (ROS). Hence, MgO/g-C3N4 nanocomposite inhibits bacterial growth.