Photocatalytic Performance of ZnO/g-C3N4 for Removal of Phenol under Simulated Sunlight Irradiation

Abstract

A ZnO/g-C3N4 photocatalyst was successfully synthesized via an impregnation method. The high-resolution transmission electron microscope (HRTEM) result shows that g-C3N4 had coated the surface of ZnO, indicating a sufficient blending between ZnO and g-C3N4 during synthesis. Reduced photoluminescence (PL) intensity of the ZnO/g-C3N4 reveals the synergic effect of the hybrid nanoparticles on the recombination of photoinduced electron–hole pairs. The resultant ZnO/g-C3N4 photocatalysts show higher degradation efficiency of phenol than that of pure ZnO under simulated sunlight irradiation. Especially, the ZnO/(5 wt%) g-C3N4 demonstrate the highest photodegradation efficiency of phenol because of the high amount of •OH radicals generated in the photocatalytic reaction. Process parameters such as photocatalyst amount, initial phenol concentration, and solution pH show a remarkable effect on the photocatalytic activity of ZnO/g-C3N4. The degradation mechanism of phenol is also detailed through identification of product intermediates and detection of reactive species. Moreover, the ZnO/g-C3N4 photocatalyst could be reused several times without appreciable loss of activity, showing great potential to be an excellent candidate for environmental remediation.