Síntese e caracterização de compósito baseado em nitreto de carbono grafítico

Abstract

The environment is undoubtedly one of the main problems that the world population faces today. New technologies are constantly being developed to improve air, water, and soil quality. In this sense, graphitic carbon nitride (g-C3N4) has been gaining prominence for its adsorption capacity associated with its photocatalytic action in the degradation of contaminants in water. However, many applications are hampered by various obstacles and shortcomings of pure g-C3N4, such as the recombination rate of high charging costs, low electrical conductivity, and lack of transport above 460 nm. The construction of semiconductor composites is an efficient approach to improve photocatalytic activity. Thus, the present work aims to synthesize and characterize a composite based on graphitic carbon nitride and zinc oxide (g-C3N4/ZnO) with different proportions of ZnO (5, 10, and 15%). To synthesize the composite g-C3N4/ZnO, the in-situ precipitation method was performed. The synthesized composites were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Diffuse Reflectance Spectroscopy (DRS), and Thermogravimetric Analysis (TGA). The characterization of the materials by infrared spectroscopy revealed that the characteristic bands of the expected organic functions and bonds are present in the structures of the composites. From the absorbance data and the estimates of Eg by the Tauc plot method, as the proportion of ZnO increases, an increase in the bandgap energy of the composites is observed, indicating the presence of strong interactions of the ZnO with the polymer sheets. The analysis of the thermal stability of the composites showed that all materials are resistant to high temperatures (up to ~350 °C) and that the mass losses due to degradation of the composites are proportional to the amount of g-C3N4 in the composites.