Investigating the synergistic effect of ZnO/GO nanocomposite films for methylene blue removal

Abstract

This study aims to reveal the growth kinetics of ZnO nanoflakes and ZnO/GO nanocomposite films obtained at different Zn precursor salt concentrations by electrochemical deposition method and to evaluate the catalytic performances of the obtained films. The films were grown on FTO substrate with Zn precursor salt concentrations of 0.1 M, 0.125 M, and 0.175 M. Characterization of the obtained films was performed by XRD, SEM, UV–vis–NIR, Raman, and XPS analyses. The strong photocatalytic capabilities of the synthesized ZnO nanoflakes and ZnO/GO nanocomposite films were demonstrated by comparative analyses with the existing literature. Accordingly, photocatalytic experiments carried out under UVA irradiation revealed the high performance of the synthesized samples in the degradation of MB dye. The reaction kinetics were investigated using the Langmuir-Hinshelwood kinetic model, resulting in high kobs values and R2 coefficients. ZnO nanoparticles showed a kobs of 0.038 min−1 and an R2 value of 0.96, while ZnO/GO nanocomposite films showed a kobs of 0.055 min−1 and an R2 value of 0.92. The significant increase in the degradation percentage shows the significant improvement achieved by the integration of GO, despite a slightly lower R2 value for the ZnO/GO nanocomposite film compared with ZnO nanoflakes films.