The synthesis of novel heterojunction h-YbFeO₃/o-YbFeO₃ photocatalyst with enhanced Fenton-like activity under visible-light

Abstract

A simple solution combustion approach followed by heat treatment was used to successfully synthesize a novel h-YbFeO3/o-YbFeO3 nanocrystalline heterojunction with an enhanced photo-Fenton-like activity in the decolorization process of methyl violet.

Synthesis, structure, and visible-light-driven activity of o-YbFeO3/h-YbFeO3/CeO2 photocatalysts

“…The presence of H2O2 makes it possible for the Fenton-like process to arise. As shown earlier in [23], Fe 2+ is formed on the surface of h-YbFeO3 during the reduction of Fe 3+ by electrons transferred from the o-YbFeO3 conduction band. During the reaction, Fe 2+ is oxidized by H2O2 to Fe 3+ and •OH radicals are formed.…”

“…For this reason, the cerium orthoferrite phase was not detected in the composition of the samples, and the presence of cerium was observed exclusively in the form of cerium (IV) dioxide. In addition, for the samples containing CeO2, the formation of the h-YbFeO3 phase is observed, which was not previously seen in this system under similar conditions without the addition of cerium [23]. The formation of the hexagonal phase of ytterbium orthoferrite in this case can be caused by the influence of the formed cerium (IV) dioxide, which creates spatial restrictions during crystallization and restricts mass transfer.…”

“…The decrease in the specific surface area in the second composition range is associated with the intensification of aggregation processes due to the increased cerium content, as a result of which the part of the nanocrystal surface is inaccessible for contact. Thus, the o-YbFeO3/h-YbFeO3/CeO2 sample has the largest specific surface area and it is 25.0 m 2 /g, which is noticeably higher than for samples based on pure o-YbFeO3 and o-YbFeO3/h-YbFeO3 composite [23].…”

“…The results of scanning electron microscopy (Fig. 6) indicate that the obtained samples have a highly porous, foamy structure, which is a consequence of the used synthetic method used, characterized by the violent release of gaseous reaction products and foaming of solid-phase products [23]. In this case, even after heat treatment, the foamy morphology is retained at the microlevel, while at the level of individual nanoparticles there are visible morphological changes.…”

Two-step combustion synthesis of nanocrystalline Zn1-xMnxFe2O4 (0<x<1) spinel ferrites with linear tuning of magnetic parameters

“…In particular, zinc-manganese ferrites should be highlighted, which have found wide application in the field of microwave technology [7], in the production of magnetic fluids [8], as contrast agents for magnetic resonance imaging [9], for drug delivery [10], etc. In addition, several works have shown the possibility of using nanostructured spinel ferrites as catalysts and photocatalysts [11], for wastewater treatment [12], as antibacterial materials [13]. For the application of this class of compounds in these areas, structural parameters are especially important, among which the size of particles and their size distribution should be singled out separately [14].…”