Příprava a charakterizace nanokompozitů na bázi grafitického C3N4 a BiIO4 pro fotokatalýzu

Abstract

This bachelor thesis deals with the preparation and characterization of nanocomposites based on the graphitized C3N4 and BiIO4 and their characterization after exposure to temperatures of 200, 300 and 400 °C. Prepared samples were characterized by the photocatalytic degradation of acid orange 7, scanning electron microscopy (including EDAX microanalysis), nitrogen physisorption, X-ray powder diffraction (for both quantitative and qualitative analysis), UV-VIS spectroscopy, infrared spectroscopy, and luminescence spectroscopy. The theoretical part deals with the conductivity in solids, catalysis and photocatalysis including kinetics of chemical reactions. Further, the properties and basic preparation methods of precursors are discussed. There is also included a brief introduction of the history of nanomaterials and nanotechnologies, their use and risks they present to health. Last but not least, the principles of the methods used are presented. The beginning of experimental part deals with used chemicals and instrumentation and parameters in mentioned analyzes. This is followed by description of the preparation of g-C3N4 and BiIO4 nanostructures and their components in a 1:1 weight ratio. There is a discussion of the results of individual analyzes and a commentary on data processing, both in tables or graphs. The measurements of photocatalytic activity showed pure BiIO4 and composite exposed to 300 °C exhibit better photocatalytic activity than other samples (respectively have the highest values of the rate constant). The XRD analysis diffraction pattern and infrared and luminescence spectroscopy of the composite exposed 400 °C showed a change in its structure in comprison with other composites. BiIO4 was transformed to BiIO during heat treatment which caused a significant change in material properties. The specific surface area (SSA) was determined by the BET analysis. BiIO4 exposed to 400 °C exhibited the lowest value of 6 m2g-1 and the highest value of 21 m2g-1 was measured for g-C3N4 exposed to 300 °C. The band-gaps energy (Eg) of materials was determined by applying the Kubelka-Munk method on DRS data and confirm a significant change in the properties of BiIO4:g-C3N4 400 composite.