Application of Spinel and Hexagonal Ferrites in Heterogeneous Photocatalysis

Abstract

Semiconducting materials display unique features that enable their use in a variety of applications, including self-cleaning surfaces, water purification systems, hydrogen generation, solar energy conversion, etc. However, one of the major issues is separation of the used materials from the process suspension. Therefore, chemical compounds with magnetic properties have been proposed as crucial components of photocatalytic composites, facilitating separation and recovery of photocatalysts under magnetic field conditions. This review paper presents the current state of knowledge on the application of spinel and hexagonal ferrites in heterogeneous photocatalysis. The first part focuses on the characterization of magnetic (nano)particles. The next section presents the literature findings on the single-phase magnetic photocatalyst. Finally, the current state of scientific knowledge on the wide variety of magnetic-photocatalytic composites is presented. A key aim of this review is to indicate that spinel and hexagonal ferrites are considered as an important element of heterogeneous photocatalytic systems and are responsible for the effective recycling of the photocatalytic materials.

Insight into (Electro)magnetic Interactions within Facet-Engineered BaFe12O19/TiO2 Magnetic Photocatalysts

“…An interesting and promising strategy to overcome this challenge is to design a photocatalyst that can be separated in an external magnetic field. However, since the material that would be both ferromagnetic and highly photocatalytic active has not been found so far, this approach usually requires combining ferromagnetic/photocatalytic materials in the form of composites. − While this approach seems generally straightforward, it creates a complex problem of possible interactions between both phases, which is especially important in the highlighted approach of photocatalyst shape engineering. Noteworthy, these interactions include not only possible electron transfer, which is a well-described phenomenon, but also possible interactions with the inner magnetic field that can be built-in within the ferromagnetic phase.…”

Structural and magnetic conduct in Sm and Al substituted Ba0.9Sm0.1Fe10Al2O19M-type hexaferrites at different sintering temperatures

“…These materials are well known for their high chemical stability, resistance to corrosion, high electrical resistivity, high saturation magnetization, low cost and high Curie temperature [2,[4][5][6]. From the last few decades M type hexaferrites of Barium, Calcium, and, Strontium hexa ferrites are in considerable attention [6][7][8][9][10][11][12]. M-type hexa ferrites can be used as EMI shielding materials to reduce electromagnetic interference, as well as in microwave absorption device, magnetic recording media, and permanent magnets [4, 6-8, 11, 13-15].…”

“…M-type barium hexaferrite have general formula BaFe 12 O 19 and is also referred as BaM [16]. Compared to their counter parts such as W-type Hexaferrites, U-type Hexaferrites, X-type Hexaferrites, Y-type Hexaferrites and Z-type Hexaferrites M-type Hexa ferrites have gained much attention owing to their superior magnetic traits [4][5][6][7][8].…”

Enhanced Photocatalytic Activity of Hierarchical Bi2WO6 Microballs by Modification with Noble Metals

“…Third, the most active titania photocatalysts are usually in the form of fine particles, which raises some problems with photocatalyst reuse and circulation (high costs of ultrafiltration). In contrast, the application of immobilized photocatalysts is connected with a low specific surface area, and thus a decrease in photocatalytic efficiency [16][17][18]. Therefore, the synthesis of highly efficient materials for the broad range of solar radiation, and easy recyclability, is a hot topic of present studies.…”