Effect of thermal behavior treatment and nickel doping impact on the structure, morphology and photocatalytic properties of NixZn1-xBi0.3Fe1.7/SiO2 nanocomposites
摘要
The present work shows the characterization of NixZn1-xBi0.3Fe1.7O4 (x = 0–0.5) incorporated into a SiO2 matrix, obtained by using a sol-gel method. The thermal analyses confirmed the development of Ni, Zn, Bi and Fe succinates at 131–190 °C and their transformation thorough decomposition into metal oxides at 260–314 °C, that subsequently undergo reactions to produce ferrites. The formation, development and decomposition of glyoxylate precursors, followed by their incorporation in the SiO2 matrix and the formation of spinel ferrite were confirmed by infrared spectroscopy. The formation of Ni-Zn-Bi ferrites with crystallite sizes in the range of 49.1–98.6 nm was established by X-ray diffraction. At high heat treatment temperatures, crystalline ferrites were integrated into the crystalline phases of the SiO2 matrix. At low heat treatment temperatures, poorly crystalline ferrites accompanied by silicates were formed. All the analyzed samples exhibit a certain degree of porosity. Mesoporous are present within a narrow pore size distribution. The photocatalytic performances of the samples investigated were evaluated by studying the degradation of Rhodamine B under the action of visible light. High amounts of Ni in the sample lead to the best removal performance, ~77%. Scavenger experiments confirm that in the photocatalytic processes involve holes, hydroxyl radicals and superoxide radicals. The photostability of the sample with Ni0.5Zn0.5Bi0.3Fe1.7O4/SiO2 was tested over five consecutive photocatalytic cycles.
Graphical Abstract