Syntheses in the Bi2O3/MoO3 system using different methods and thermal characterization of products

Namen magistrskega dela je bil sintetizirati bizmut molibdenove nanodelce z različnimi metodami ter oceniti fotokatalitsko učinkovitost enega izmed produktov pri razbarvanju RhB ob prisotnosti vidne svetlobe. Prvi sklop eksperimentalnega dela je zajemal sintezo bizmut molibdenovih nanodelcev z različnimi kristalnimi strukturami . Pri tem smo uporabljali mehanokemijsko, hidrotermalno, sonokemijsko in metodo nizko temperaturne taline soli (LTMS). Pripravljeni produkti so bili karakterizirani z rentgensko praškovno difrakcijo (RTG), presevnim elektronskim mikroskopom (TEM) in termogravimetrično analizo (TGA). Fotokatalitsko aktivnost bizmut molibdenovega kristala smo ocenili z izvedbo fotokatalitske degradacije rodamina B pri sobni temperaturi pod vplivom VIS sevanja. Rezultati so pokazali, da smo uspeli sintetizirali vse tri fazne modifikacije bizmutovih molibdatov. Z mehanokemijsko sintezo smo sintetizirali alfa in gama bizmut molibdenove nanodelce, hidrotermalna sinteza je pripomogla k nastanku gama in beta modificiranih bizmutovih molibdatov ter s sonokemijsko sintezo smo ustvarili beta bizmut molibdenov oksid. Z uporabo UV-VIS spektrofotometra smo Bi2Mo3O12 nanodelcem ocenili fotokatalitske sposobnosti degradacije rodamina B (RhB) v raztopini pri sobni temperaturi pod vplivom VIS sevanja. Ugotovljeno je bilo, da je absorpcijski rob Bi2Mo3O12 ocenjen pri 435 nm, kar ustreza vrednosti prepovedanega pasu Eg = 2,78 eV. V prisotnosti obeh ključnih dejavnikov tako svetlobe kot fotokatalizatorja (Bi2Mo3O12) smo po 120 minutah obsevanja z vidno svetlobo dosegli skoraj 100 % razgradnjo RhB. The purpose of the master's thesis was to synthesize bismuth molybdenum nanoparticles using various methods and to evaluate the photocatalytic efficiency of one of the products in RhB discoloration in the presence of visible light. The first set of experimental work involved the synthesis of bismuth molybdenum nanoparticles with different crystal structures. Mechanochemical, hydrothermal, sonochemical and low temperature salt melt (LTMS) methods were used. The prepared products were characterized by X-ray powder diffraction (RTG), transmission electron microscope (TEM) and thermogravimetric analysis (TGA). The photocatalytic activity of bismuth molybdenum crystal was evaluated by performing photocatalytic degradation of rhodamine B at room temperature under the visible light irradiation. The results showed that we were able to synthesize all three phase modifications of bismuth molybdates. Alpha and gamma bismuth molybdenum nanoparticles were synthesized by mechanochemical synthesis, hydrothermal synthesis helped to produce gamma and beta modified bismuth molybdates and sonochemical synthesis created beta bismuth molybdenum oxide. Using the UV-VIS spectrophotometer, Bi2Mo3O12 nanoparticles were evaluated for photocatalytic degradation of rhodamine B (RhB) in solution at room temperature under the VIS radiation. The absorption edge of Bi2Mo3O12 was found to be estimated at 435 nm, which corresponds to the bandgap value Eg = 2.78 eV. In the presence of both key factors, light and photocatalyst (Bi2Mo3O12), we achieved almost 100% degradation of RhB after 120 minutes of visible light irradiation.