Síntese e caracterização da heterojunção de g-C3N4 com ZnO impregnado com nanopartículas de prata

Abstract

This study details the synthesis and characterization of the heterojunction between zinc oxide (ZnO) and graphitic carbon nitride (g-C3N4) impregnated with silver nanoparticles (NPsAg), aiming to investigate the structural and optical properties of these materials to enhance their performance in photoreduction. The materials were obtained through a simple combination method, which includes mixing, sonication, and thermal treatment steps. Characterization tech- niques such as X-ray diffraction (XRD), UV-Vis spectroscopy, and photoluminescence confirmed the interaction between these materials. XRD identified the crystalline phases of g-C3N4 and ZnO and their interactions with NPsAg, while photoluminescence analysis revealed reduced recombination in the heterojunction compared to pure g-C3N4. Band gap calculations from diffuse reflectance spectroscopy (DRS) for pure g-C3N4 and modified photocatalysts showed values consistent with those reported in the literature. The g-C3N4/ZnO and g-C3N4/Ag/ZnO heterojunctions demonstrated high efficiency in reducing Fe2+ to Fe0 compared to pure g-C3N4 and g-C3N4/Ag. Results showed that the g-C3N4/ZnO and g-C3N4/Ag/ZnO heterojunctions adsorbed 10 times more Fe2+ than pure g-C3N4, attributed to charge transfer effects and the presence of ZnO. The addition of 1% Ag significantly increased adsorption in the heterojunctions and enhanced photocatalytic efficiency, resulting in a higher reaction rate coefficient for photoreduction.