Ferrite Materials for Photoassisted Environmental and Solar Fuels Applications

Abstract

Ferrites are a large class of oxides containing Fe 3+ and at least another metal cation that have been investigated for and applied to a wide variety of fields ranging from mature technologies like circuitry, permanent magnets, magnetic recording and microwave devices to the most recent developments in areas like bioimaging, gas sensing, and photocatalysis. In the last respect, although ferrites have been less studied than other types of semiconductors, they present interesting properties such as visible light absorption, tuneable optoelectronic properties and high chemical and photochemical stability. The versatility of their chemical composition and of their crystallographic structure opened a playground for developing new catalysts with enhanced efficiency. This article reviews the recent development of the application of ferrites to photoassisted processes for environmental remediation and for the synthesis of solar fuels. Applications in the photocatalytic degradation of pollutants in water and air, photo-Fenton, and solar fuels production, via photocatalytic and photoelectrochemical water splitting and CO2 reduction, are reviewed paying special attention to the relationships between the physico-chemical characteristics of the ferrite materials and their photo-activated performance.

Recent Achievements in Development of TiO2-Based Composite Photocatalytic Materials for Solar Driven Water Purification and Water Splitting

“…The degradation improvement was ascribed to the addition of H 2 O 2 in the system, which generated more ROS than by the common photocatalytic mechanisms described above [41]. Hence, the contribution of H 2 O 2 in such a system can be described through restraining e − /h + recombination and increasing HO• generation in the system, as in Equation 1 [42,43]. Spinel ferrites band positions match TiO 2 , thus possessing compatibility to form a heterojunction (Type II Heterojunction) [44][45][46][47].…”

Synthesis, Characterization, and Applications of CoFe2O4 and M-CoFe2O4 (M = Ni, Zn, Mg, Cd, Cu, RE) Ferrites: A Review

“…For instance, large angles and short distances between cations would enhance the exchange coupling and hence corresponding magnetic properties. The angles in the spinel structure for the A-A, B-B, and A-B interactions are 79.63°, 90°/125.3°, and 125.15°/154.57°, respectively [96], so that the A-B exchange interactions are the strongest [100,101,104].…”

Advanced Functional Electroactive and Photoactive Materials for Monitoring the Environmental Pollutants

“…In general, a heterojunction can be schematically described as the interface between two different semiconductors with unequal band structure, which can result in band alignments. [ 162 ] As illustrated in Figure 14a, if the VB and CB of semiconductor A are higher than that of semiconductor B, the photogenerated electrons will migrate from the CB of semiconductor A to that of semiconductor B with a lower reduction potential, and at the same time, the corresponding holes in the VB of semiconductor B will migrate to semiconductor A with a lower oxidation potential, leading to the spatial separation of electron–hole pairs. [ 163 ] Consequently, conventional heterojunction constructed with two crystal semiconductors with a staggered gap appears to be an effective structure for improving the PEC performance of semiconductors and has been employed in the construction of high‐performance PEC sensing platforms.…”