Study on the photocatalytic activity of ZnO/g-C3N4 heterojunction for phenol degradation under visible light irradiation

In this study, the ZnO/g-CN heterostructure material was synthesized via a simple method, in which ZnO was first obtained through a precipitation process and then calcined with urea to form the final product.Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and diffuse reflectance UV-Vis spectroscopy (DR/UV-Vis) were employed to investigate the crystal structure, surface morphology, particle size, and light absorption properties of the material.The results revealed that the ZnO/g-CN material exhibited nanoparticle sizes in the 25 -40nm range.The photocatalytic performance was evaluated by the degradation of phenol under visible light, achieving a high degradation efficiency of 87.5% within 120 minutes, with a pseudo-first-order kinetic rate constant (k) of 0.016 min -1 .Additionally, the material showed a low electrical energy consumption per order (EEO) of only 92.28WhL -1 , indicating its promising potential for wastewater treatment applications.The Z-scheme charge transfer mechanism between ZnO and g-CN enhanced the separation of photogenerated electron-hole pairs (e⁻-h⁺), thereby promoting the formation of reactive radicals and improving the degradation efficiency of recalcitrant organic compounds.