Spinel Ferrite Materials Research Articles

The effect of conduction loss on microwave absorption performance of Fe-doped NiCo2O4 spinel oxide

Strong absorption and large bandwidth are two contributors to material’s electromagnetic wave absorbing performance. While spinel ferrite materials have garnered extensive attention in the realm of microwave absorption, their relatively low conductivity remains a practical challenge.In this work, NiCo2-xFexO4 (x = 0, 0.04, 0.06 and 0.08) precursor was prepared by hydrothermal and after-sintered method. It was found that Fe doping exhibit excellent EM absorption properties. Specially, when the Fe content is 0.08, the maximum reflection loss −48.90 dB at 15.40 GHz and the maximum effective bandwidth 4.20 GHz are achieved. More importantly, the absorption frequency can be broadened from Ku to C band even to S band with proper adjusting Fe content. Doping with Fe enhances conduction loss and make a significant contribution to dielectric loss, as a result, the impedance matching degree of the Fe-NiCo2O4 composite is influenced by the synergistic effect of its dielectric and magnetic properties. This work provides a simple way for enhancing the microwave absorption capabilities of ferrite materials and provides insight into understanding conduction loss in microwave absorption.

Pemanfaatan Ekstrak Daun Sirih Hijau (Piper Betle Linn.) sebagai Capping Agent dalam Green Synthesis Spinel Ferit ZnFe2O4 untuk Remediasi Fenol dalam Air dan sebagai Anti Bakteri

The spinel ferrite material ZnFe2O4 was synthesized using a green synthesis approach by the hydrothermal method. In the synthesis, 2M NaOH was used as a mineralizer and betel leaf extract with varying volumes of 1, 3, 5, and 7 mL as a capping agent, then continued with calcination at 500, 600, and 700°C. Several devices, such as XRD, FT-IR, SEM-EDX, DRS-UV-Vis, and VSM, were used to characterize the synthesized ZnFe2O4 material. The pattern of XRD indicated that the ZnFe2O4 material has a cubic structure, where the increase in crystal size was after calcination. The Fourier Transform Infra-Red (FT-IR) spectrum shows the Fe-O interaction at wave numbers 427-417 cm-1, which is located on the octahedral side, while the Zn-O interaction at wave numbers 534-510 cm-1, which is located on the tetrahedral side in spinel ferrite structure. From the DRS UV-Vis spectrum pattern and band gap values, it was found that the material absorbs light in the visible region. Scanning Electron Microscope (SEM) images show that the morphology of the synthesized material is circular. The Vibrating Sample Magnetometer (VSM) hysteresis curve shows that the synthesized ZnFe2O4 has paramagnetic properties. The synthesized ZnFe2O4 material has photocatalytic activity towards phenolic compounds with a degradation percentage reaching 62.2%, and this material is active as an antibacterial with an inhibition area of 14.4 for S. aereus bacteria.

Mn-Zn spinel ferrite synthesis by solution combustion method and applications in adsorption of dyes

Dyes are hazardous chemicals that are commonly found in textile industries’ effluent water. Adsorption techniques are more efficiently used for the removal of various dyes from wastewater. The present work deals with the synthesis of Mn-Zn (Mn0.3Zn0.7Fe2O4) spinel ferrite through the solution combustion method. The solution combustion method has many advantages over other conventional methods. Single-phase spinel ferrite materials can be synthesized by using this method at lower temperatures and in a shorter time. Synthesized Mn-Zn spinel ferrite material has been characterized by using FT-IR spectroscopy. As synthesized ferrite material has been employed for the adsorption of various dyes with different concentrations from their aqueous solutions. Results related to dyes’ adsorption have been reported using UV-Visible spectroscopy. Mn- Zn spinel ferrite has worked efficiently as an adsorbent and its magnetic nature is useful for its extraction from the aqueous solution.

Enhanced medicinal applications of Co-doped Zn0.5Ni0.5Fe2-xO4 for (X = 0.00 and 0.0250) soft ferrites: A structural analysis

In this experimental research paper, we investigate the potential enhancement of Co-doped Zn0.5Ni0.5Fe2-xCoxO4 for (x = 0.0, and 0.0250) ferrites, synthesis by green synthesis method for applications in medicine. The structural analysis of the synthesized material is a crucial step in understanding its suitability for medical applications. X-ray Diffraction (XRD) is employed to elucidate the crystallographic structure of the Co-doped ZnNiFe2O4 ferrites. The results demonstrate that the doping process has a significant influence on the material’s crystal structure, which may impact its potential in various biomedical applications. The Co-doped ZnNiFe2O4 spinel ferrite materials become more suitable for medical applications as the decrease in X-ray density and simultaneous increase in bulk density can facilitate better tissue penetration and biocompatibility, making them ideal for non-invasive medical imaging and therapeutic applications, while minimizing potential health risks.

Multi-interfacial 1D magnetic ferrite@C fibers for broadband microwave absorption

As a classical magnetic material, spinel ferrite materials have been widely studied in the field of microwave absorption. However, due to their low conductivity and uncontrollable self-aggregation, their practical application has been greatly constrained. Now, a novel multi-interfacial one-dimensional (1D) magnetic ferrite@C fibers composites were synthesized by a facile electrospinning and annealing process. Through effective structural design and component adjustment, Zn-based ferrites were successfully confined into 1D carbon fibers. This structure brings about a large number of heterogeneous interfaces, while avoiding magnetic aggregation. Impressively, the results indicate that as-prepared ferrite@C fibers exhibit excellent EM absorption properties. The minimum reflection loss can reach up to −47.42 dB at 13.52 GHz with a matching thickness of 2.5 mm. In the meantime, a super-wide effective absorption bandwidth of 9.28 GHz (8.24–17.52 GHz) is obtained at 3.3 mm, which almost concurrently achieves coverage for X and Ku-bands. This study provides a feasible path to design novel and efficient magnetic ferrite/dielectric absorbers.

Contact electrification of porous PDMS-nickel ferrite composites for effective energy harvesting

Energy harvesting technologies are becoming popular owing to their usage in the operation of low-power consumer electronics and as an alternative power source. Specifically, triboelectric nanogenerators (TENGs) have drawn much attention as they can efficiently scavenge waste mechanical energy into electrical output. Careful material selections can further improve the performance of TENGs. In this work, a spinel ferrite material with the chemical formula NiFe2O4 (NFO abbreviated further) is synthesized using a solid-state reaction route. The structural and magnetic property of the NFO has been studied, showing the cubic symmetry and ferromagnetic nature of the sample. The 3D tomography images of the PDMS-NFO composites were carried out using X-ray tomographic microscopy. To enhance the performance of the TENGs, we adopted a porous media by evaporation of water during the curing process of PDMS-NFO composites. A single-electrode operating mode was adopted for TENG fabrication. The electrical response of the device was carried out using different wt% and frequencies. The 12 wt% of NFO in PDMS (PN12 device) delivered a voltage, current, and charge of 60 V, 300 nA, and 34 nC, respectively. The charge density of the plain and porous composite-based TENG was compared to confirm the enhancement of the charge produced on the triboelectric layers. The commercial capacitors and energy harvesting based on a smart home were demonstrated using the TENG devices.

Analysis on the cation distribution of Mg x Ni1−x Fe2O4 (x = 0, 0.25, 0.5, 0.75, 1) using Mössbauer spectroscopy and magnetic measurement

Mg x Ni1−x Fe2O4 (x = 0, 0.25, 0.5, 0.75, 1) spinel ferrite material was analyzed to determine its magnetic properties and structure. X-ray diffraction (XRD), Mössbauer spectroscopy, and vibrating sample magnetometer (VSM) characterization were performed on the samples prepared using the sol–gel method. The results from XRD confirmed the existence of the single-phase cubic spinel structures , as well as the evolution of the crystalline size (D), the lattice parameter (a) and cell volume in compounds. The Mössbauer spectra showed the distribution of cations and changes in the magnetic properties of the sample. VSM measurement revealed that the samples were room-temperature ferromagnetic. Moreover, the saturation magnetization (M s) of the samples changed with the Mg2+ ion content x, and a maximum occured at x = 0.5. Doping with Mg2+ ions increased the transfer of Ni2+ ions to tetrahedral sites, thus increasing the magnetic moment difference between tetrahedral (A) and octahedral (B) sites. Specifically, doping NiFe2O4 with Mg2+ ions can enhance its magnetic properties and enhance its saturation magnetization.

Recent advances in magnetic semiconductor ZnFe2O4 nanoceramics: History, properties, synthesis, characterization, and applications

Zinc ferrite or franklinite (ZnFe2O4) is a kind of cubic spinel ferrite material with magnetic properties, which has been studied since 1915's. ZnFe2O4 is widely used in catalytic processes and energy-related fields thanks to its narrow bandgap energy, although they are used as radar and microwave absorbent, pollutant adsorbent, etcetera. One of the favorable properties of ZnFe2O4 is that it can be hybridized, doped, and combined with other materials like polymers, metals, etc. Here, we tried to introduce the brief and general aspects of ZnFe2O4 chemistry, synthesis, properties, characterization, and some examples of its applications.

Hematite: A Good Catalyst for the Thermal Decomposition of Energetic Materials and the Application in Nano-Thermite

Metal oxides (MOs) are of great importance in catalysts, sensor, capacitor and water treatment. Nano-sized MOs have attracted much more attention because of the unique properties, such as surface effect, small size effect and quantum size effect, etc. Hematite, an especially important additive as combustion catalysts, can greatly speed up the thermal decomposition process of energetic materials (EMs) and enhance the combustion performance of propellants. This review concludes the catalytic effect of hematite with different morphology on some EMs such as ammonium perchlorate (AP), cyclotrimethylenetrinitramine (RDX), cyclotetramethylenete-tranitramine (HMX), etc. The method for enhancing the catalytic effect on EMs using hematite-based materials such as perovskite and spinel ferrite materials, making composites with different carbon materials and assembling super-thermite is concluded and their catalytic effects on EMs is also discussed. Therefore, the provided information is helpful for the design, preparation and application of catalysts for EMs.

Structural, electrical and magnetic properties of (Cu/Co)Fe2O4 spinel ferrite materials

Structural, electrical and magnetic properties of (Cu/Co)Fe2O4 spinel ferrite materials

Investigation of the structural, optical, electrical and dielectric proprieties of LiCd0.5Fe2O4 spinel ferrite

The spinel ferrite material families are subjected to diverse studies according to their wide field application. In this work, the LiCd0.5Fe2O4 ferrite was successfully synthesized by a conventional solid-state method. The structural, optical, electrical and dielectric characterizations were treated. The Rietveld refinement method explored cubic spinel structure (Fd3‾m space group) with a lattice parameter: a = 8.628 Å, α = 90°. Besides, the surface micrograph shows a strong agglomeration of the grains. Optical results were calculated using diffuse reflectance data and Kubelka Munk theory. They show the semiconductor nature with a band gap around 2.9 eV and Urbach energy around 0.14 eV.The electrical measurements were studied over a range of frequency (40 Hz–1 MHz) and through large temperature scale (200 K–380 K) using the complex impedance spectroscopy technique. The AC conductivity behavior was described by the jump relaxation model, which obeys to the Jonscher's law. The complex impedance analysis has suggested the presence of the contribution of the grains, the grain boundaries and interface in the conduction mechanism. A reduction in real part Z′ was observed as a function of temperature and frequency, which indicates an increase in ac conductivity and a negative temperature coefficient of resistance. Hence, the complex modulus plots have affirmed the presence of grain boundaries contribution in the material. Both the complex modulus and impedance investigations have confirmed that the synthesized material exhibits a non-Debye type of relaxation. Finally, the dielectric behavior of the studied sample shows a polarization effect and the permittivity graphs are fitted theoretically with the Cole-Cole model.

Fe3+ in a tetrahedral position determined the electrocatalytic properties in FeMn2O4.

As an electrocatalyst for the oxygen evolution reaction (OER) for water decomposition purposes, spinel ferrite materials have gained a lot of attention from many researchers. Herein, we document a co-precipitation synthesis of antitypical spinel nanoparticles (FeMn2O4) by post-annealing at different temperatures to enable modulation of the cationic oxidation state and tuning of the conversion degree for efficient and good OER performance. The electrocatalytic activity test shows that the sample annealed at 500 °C has the most optimal catalytic activity with an overpotential of 360 mV at a current density of 10 mA cm−2 and a Tafel slope as low as 105.32 mV dec−1. The formation of FeOOH during in situ OER promotes the catalytic activity of the catalysts. More importantly, according to the results of Brunauer–Emmett–Teller normalization, we demonstrate that the activity of the catalyst is also inseparable from the internal crystal structure. This work broadens the field of research on the electrocatalysis of spinel manganese ferrites.

Structural and Magnetic Properties of Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4/ZnFe2O4 Spinel Ferrite Nanocomposites: Comparative Study between Sol-Gel and Pulsed Laser Ablation in Liquid Approaches.

In this study, the samples of the ZnFe2O4 (ZFO) spinel ferrites nanoparticles (SFNPs), Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4 (CNGaGdFO) SFNPs and (Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4)x/(ZnFe2O4)y (x:y = 1:1, 1:2, 1:3, 2:1, 3:1 and 4:1) (CNGaGdFO)x/(ZFO)y spinel ferrite nanocomposites (NC) have been synthesized by both sol-gel and Green pulsed laser ablation in liquid (PLAL) approaches. All products were characterized by X-ray powder diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM), elemental mappings and energy dispersive X-ray spectroscopy (EDX). It was objected to tune the magnetic properties of a soft spinel ferrite material with a softer one by mixing them with different fractions. Some key findings are as follows. M-H investigations revealed the exhibition of ferrimagnetic phases for all synthesized samples (except ZnFe2O4) that were synthesized by sol-gel or PLAL methods at both 300 K and 10 K. ZnFe2O4 ferrite NPs exhibits almost paramagnetic feature at 300 K and glass-like phase at very low temperatures below 19.23 K. At RT analyses, maximum saturation magnetization (MS) of 66.53 emu/g belongs to nanocomposite samples that was synthesized by sol-gel method and x:y ratio of 1:3. At 10 K analyses, MS,max = 118.71 emu/g belongs to same nanocomposite samples with ratio of 1:3. Maximum coercivities are 625 Oe belonging to CNGaGdFO and 3564 Oe belonging to NC sample that was obtained by sol-gel route having the 3:1 ratio. Squareness ratio (SQRs = Mr/MS) of NC sample (sol-gel, 4:1 ratio) is 0.371 as maximum and other samples have much lower values until a minimum of 0.121 (laser, 3:1) assign the multi-domain wall structure for all samples at 300 K. At 10 K data, just CNGaGdFO has 0.495 SQR value assigning single domain nature. The maximum values of effective crystal anisotropy constant (Keff) are 5.92 × 104 Erg/g and 2.4 × 105 Erg/g belonging to CNGaGdFO at 300 K and 10 K, respectively. Further, this sample has an internal anisotropy field Ha of 1953 Oe as largest at 300 K. At 10 K another sample (sol-gel, 3:1 ratio) has Ha,max of 11138 Oe which can also be classified as a soft magnetic material similar to other samples. Briefly, most magnetic parameters of NCs that were synthesized by sol-gel route are stronger than magnetic parameters of the NCs that were synthesized by PLAL at both temperatures. Some NC samples were observed to have stronger magnetic data as compared to magnetic parameters of Co0.5Ni0.5Ga0.01Gd0.01Fe1.98O4 NPs at 10 K.

The effects of fuel type onto the structural, morphological, magnetic and photocatalytic properties of nanoparticles in the synthesis of cobalt ferrite nanoparticles with microwave assisted combustion method

In this experimental study, the synthesis of cobalt ferrite nanoparticles, one of the most important types of ferromagnetic spinel ferrite materials was realized by using a method known as microwave assisted combustion method. The effects of the substance used as fuel on the structural, morphological, magnetic and photocatalytic properties of synthesized nanoparticles were investigated. Firstly, samples were prepared using urea, glycine and citric acid as fuel and then the samples were comprehensively characterized by advanced analysis techniques such as XRD, FT-IR, TEM, SEM, VSM, BET. Moreover, the usability of the obtained nanoparticles in photocatalytic degradation process of Procion Yellow H-E3G textile dye as photocatalyst was investigated. The results obtained indicate that the fuel used is highly effective on various properties of the synthesized materials. From the experiments performed to evaluate the photocatalytic performances of the nanoparticles, it was observed that each of the three different fuel matters used for the synthesis of nanoparticles were highly effective on the photocatalytic degradation of the organic pollutant. Furthermore, almost all the dye content in solution was completely removed at the end of the experimental period which lasted for 90 min.

Effect of Nd-Y co-substitution on structural, magnetic, optical and microwave properties of NiCuZn nanospinel ferrites

Partially Nd/Y substituted [Ni0.4Cu0.2Zn0.4](NdxYxFe2-2x)O4 (x ≤ 0.05) spinel ferrite nanoparticles (NSFs) were prepared by citrate sol-gel auto-combustion technique. UV–vis Percent to determine optoelectronic properties mixed spinel ferrite materials. Direct energy band gaps values are within 1.87 and 1.92 eV interval. The magnetization features were investigated at room temperature (RT; T = 300 K) versus magnetic field ((M-H)). RT M-H curves showed superparamagnetic (SPM) behavior in non-substituted sample (x = 0.00), while all the Nd-Y substituted NiCuZn ferrite NPs exhibited soft ferrimagnetic (FM) character. It is found that the magnitude of magnetization drops with a rise in Nd3+ and Y3+ contents. ZFC–FC magnetization curves revealed the existence of dipolar interactions, which illuminate a partially blocked state in accordance with M-H loops at 300 K. The electrodynamic data reflection coefficients for Ni0.4Cu0.2Zn0.4](NdxYxFe2-2x)O4 (x ≤ 0.05) NSFs were determined. The occurrences of the electromagnetic absorption between 49 to 4.15 GHz frequency range were observed. A significant linking amongst the ratio (x) and amplitude-frequency characteristics (AFC) was investigated. Additionally, the AFC of the Ni0.4Cu0.2Zn0.4](NdxYxFe2-2x)O4 (x ≤ 0.05) NSFs were strongly influenced with the increase of Nd/Y concentration. It was demonstrated that low level of the concentration substitution (less than 10 at.%) not critically effected on resonance characteristics. We found that an anomalous altering of the resonant amplitude (almost 2 times) resulted due the manifestation of indirect exchange interactions amongst iron (III), yttrium (III) and neodymium (III) electronic shells. Almost a linear behavior of the main AFC was observed.

Influenced of Cu<sup>2+</sup> Doped on Structural, Morphological and Optical Properties of Zn-Mg-Fe<sub>2</sub>O<sub>4</sub> Ferrite Prepared by Sol-Gel Method

The Zn0.5CuxMg0.5-xFe2O4 (where x = 0.0, 0.1, 0.2, 0.3 and 0.4) was prepared by sol-gel route and characterized in detail in terms of their structural, morphological, elemental and optical properties as a function of Cu concentration. X-ray diffractometer (XRD) results confirmed the formation of cubic spinel-type structure with average crystallized size in the range of 30.56 to 40.58 nm. Lattice parameter was found to decrease with Cu concentration due to the smaller ionic radius of Cu2+ ion. The HR-SEM images show morphology of the samples as prismatic shaped particles in agglomeration. The elemental dispersive X-ray Spectroscopy (EDX) confirmed the elemental composition of the as-prepared spinel ferrite material with respect to the initial concentration of the synthetic composition used for the material. The Fourier transform infrared (FTIR) spectroscopy confirmed the formation of spinel ferrite and showed the characteristics absorption bands around 463, 618, 876, 1116, 1442, 1622 and 2911 cm-1. The energy band gap was calculated for the samples were found to be in the range of 4.87 to 5.30 eV.

Impact of molybdenum on structural and morphological properties of manganese ferrite nanoparticles by hydrothermal method

The study of transition metal ferrites have vast applications from microwave to radio-wave frequencies and are of great importance from both fundamental as well as in research aspect. Based on their magnetic properties, transition metal ferrites are found to have low magnetic anisotropies and are magnetically categorized as soft. Manganese ferrites are a group of soft spinel ferrite materials with high magnetic permeability, high electrical resistance and low loss. The doping of molybdenum improves its resistivity, strength and toughness. Due to their excellent electrical and magnetic properties, spinel ferrites are technologically important ceramic materials. As transition takes place from micron to nano regime, these materials are found to be with excellent chemical stability, moderate saturation magnetization and low eddy currents especially in spinel ferrites. In this present work, nanocrystalline ferrites MnxMo1-xFe2O4 of x varies as 0.4, 0.6 and 0.8 are synthesized by hydrothermal method. The prepared nanocrystalline ferrites are characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Energy Dispersive X-Ray Analysis (EDX) and Scanning Electron Microscopy (SEM) for analyzing its structural, functional groups and morphological structures. XRD analysis reveals that the resultant ferrite nanoparticles are found to have cubic structure. FT-IR spectral analysis shows two main broad metal–oxygen bands and confirms the presence of spinel ferrites. EDX analysis confirms the quantitative presence of elements without impurities. This study aims to fabricate the ferrites with better physical and magnetic properties that are useful in a variety of applications such as magnetic sensors, heavy metal removal and transducers.

Impact of sonochemical synthesis condition on the structural and physical properties of MnFe2O4 spinel ferrite nanoparticles.

Herein, we report sonochemical synthesis of MnFe2O4 spinel ferrite nanoparticles using UZ SONOPULS HD 2070 Ultrasonic homogenizer (frequency: 20 kHz and power: 70 W). The sonication time and percentage amplitude of ultrasonic power input cause appreciable changes in the structural, cation distribution and physical properties of MnFe2O4 nanoparticles. The average crystallite size of synthesized MnFe2O4 nanoparticles was increased with increase of sonication time and percentage amplitude of ultrasonic power input. The occupational formula by X-ray photoelectron spectroscopy for prepared spinel ferrite nanoparticles was (Mn0.29Fe0.42)[Mn0.71Fe1.58]O4 and (Mn0.28Fe0.54) [Mn0.72Fe1.46]O4 at sonication time 20 min and 80 min, respectively. The value of the saturation magnetization was increased from 1.9 emu/g to 52.5 emu/g with increase of sonication time 20 min to 80 min at constant 50% amplitude of ultrasonic power input, whereas, it was increased from 30.2 emu/g to 59.4 emu/g with increase of the percentage amplitude of ultrasonic power input at constant sonication time 60 min. The highest value of dielectric constant (ε') was 499 at 1 kHz for nanoparticles at sonication time 20 min, whereas, ac conductivity was 368 × 10-9 S/cm at 1 kHz for spinel ferrite nanoparticles at sonication time 20 min. The demonstrated controllable physical characteristics over sonication time and percentage amplitude of ultrasonic power input are a key step to design spinel ferrite material of desired properties for specific application. The investigation of microwave operating frequency suggest that these prepared spinel ferrite nanoparticles are potential candidate for fabrication of devices at high frequency applications.

Structural and Magnetic Properties of Spinel Ferrite Nanoparticles.

In this paper we review the magnetic properties of spinel ferrite nanoparticles pointing out the primary role of the crystalline structure besides finite size and surface/interface effects. The details of the spinel crystal structure of bulk spinel ferrite materials and their influence on both the magnetization and magnetocrystalline anisotropy are recalled. Moreover, we review some results published in the literature over the last years about how the structure of magnetic nanoparticles influences their magnetic features. Perspectives about the challenges to improve the applications in several fields are finally reported.

Assembly and photochemical properties of mesoporous networks of spinel ferrite nanoparticles for environmental photocatalytic remediation

Spinel ferrite materials have an electronic band structure that is well suited for visible light-induced catalysis, however, their photocatalytic activity remains low due to the daunting charge-carrier separation process. In this article, we report that high-surface-area mesoscopic architectures composed of tightly connected ultrasmall spinel ferrite nanocrystals can efficiently suppress electron-hole recombination, manifesting an exceptional activity and magnetic recyclability in photocatalytic reduction of aqueous Cr(VI). Revealed by electron microscopy, N2 physisorption, and X-ray scattering studies, the resulting materials, which were obtained through a block copolymer-assisted cross-linking aggregation of colloidal nanoparticles, show a 3D interconnected nanoporous structure with a large internal surface area (up to 159 m2 g−1) and exhibit small grain composition (ca. 6–8 nm in size). Through a systematic synthesis of various structural analogues to the spinel ferrite family and optical absorption and electrochemical impedance spectroscopy analyses, we demonstrate that the electronic band structure fits the electronic requirements for both Cr(VI) reduction and water oxidation under UV–vis light irradiation. Among spinel ferrites, ZnFe2O4 presents the highest activity, readily operating without additional sacrificial reagents in photocatalytic detoxification of aqueous Cr(VI), which together with transient gas analysis and fluorescence spectroscopy results suggest a competitive formation of oxygen and hydroxyl radicals at the catalyst surface. These findings provide an essential tool for the delineation of the electronic structure-catalytic property relationship in spinel ferrite nanostructures offering intriguing possibilities for designing new photocatalytic systems for efficient environmental pollution purification and energy conversion.