Synthesis of cost-effective g-C3N4/ZnO heterostructure photocatalyst for methyl orange (MO) dye degradation

Abstract

In the present work a composite photocatalyst (g-C3N4/ZnO) was prepared via single step calcination process. The g-C3N4 is useful as photocatalyst in the visible range of the solar spectrum but it has major drawbacks like less surface adsorption ability and low ability of photo induced charge carrier's separation, which limits its photocatalytic efficiency. The g-C3N4/ZnO heterostructure has been synthesized to utilize the advantages of ZnO, e.g., its larger specific surface area and higher charge carrier mobility. The structural characterization of the composite heterostructure was done by using XRD, and HRTEM tools. Optical band gap was determined from the UV-vis diffuse reflectance spectra. The g-C3N4/ZnO composite exhibits the band gap ∼2.78 eV. The methyl orange (MO) dye was used for the photocatalytic activity study under 400 W, 150 min of visible light irradiation. The photodegradation efficiency of g-C3N4/ZnO heterostructure was increased significantly to a rate constant 0.0117 min−1 which is almost three times better than that of g-C3N4 (∼0.00396 min−1). Due to the synergistic effect and efficient charge transfer between g-C3N4 and ZnO, superior photodegradation with highest rate constant was achieved.