Oxygen-vacancy-controlled magnetic properties with magnetic pole inversion in BiFeO3-based multiferroics

Oxygen vacancies which are generally present in ferrite oxide may significantly affect their magnetic properties. A comprehensive understanding of the relationship between oxygen vacancies and magnetism is of great importance. In this work, we report an oxygen vacancy concentration dependence of magnetism in a single-phase multiferroic BiFeO₃ (BFO)-based system. The BiFeO₃-DyFeO₃ (BDFO) solid solution is synthesized with controlled oxygen vacancies and is characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and AC impedance spectroscopy. The magnetic properties, especially magnetic pole inversion, are found to be highly dependent on oxygen vacancy concentration. The oxygen vacancies generate a Weiss molecular field on the Dy³⁺ ions in the magnetic field range of 570-1000 Oe depending on the oxygen vacancy concentration, and result in a residual net magnetization by breaking the balance between the two nearly antiparallel spin lattices of Fe³⁺ ions. This work demonstrates an effective way to control oxygen vacancies and thereby the magnetic properties and sheds light on the relationship between oxygen vacancies and magnetism in BFO-based multiferroics.     

Structural and magnetic properties of porous FexOy nanosheets and nanotubes fabricated by electrospinning

2D porous α-Fe₂O₃ nanosheets and 1D porous Fe_xO_y nanotubes were synthesized using electrospinning technique under different conditions. XRD results show that the α-Fe₂O₃ nanosheets are pure α-Fe₂O₃ phase, and the Fe_xO_y nanotubes are mainly composed of α-Fe₂O₃ phase accompanied by weak Fe₃O₄ phase. The EDX mappings demonstrate that the elements of O and Fe were uniformly distributed in nanosheets and nanotubes. The valence of iron ion is pure 3?+ in the α-Fe₂O₃ nanosheets, and it shows 3?+ with a small amount of 2?+ in the Fe_xO_y nanotubes. Magnetic properties of the synthesized samples were studied by vibrating sample magnetometer and Mössbauer spectrometer, the results show that the α-Fe₂O₃ nanosheets have the room temperature ferromagnetism and the Fe_xO_y nanotubes have a higher saturation magnetization of 18.91?emu/g. Mössbauer spectrometer proved further the microstructure of nanosheets and nanotubes, which are consistent with the results of XPS. Our results will be helpful for the application of nanoporous materials.     

Phase equilibria in the Fe-V-O system near “FeO”-V2O3 isopleth

Phase equilibria in the “FeO”-V₂O₃ system from 1273 to 1808 K and in the range of oxygen partial pressure from 10⁻¹⁵ to 10⁻⁴ atm are investigated. High-temperature quenching, XRD, SEM-EDS, and DSC are used to determine the phase relations. Stable regions of (FeO)_s.s., (V₂O₃)_s.s., and spinel phases are considerably effected by the oxygen partial pressure, and structural models are proposed as (Fe²⁺, Fe³⁺, V²⁺)_1-xO, (V²⁺, V³⁺, V⁴⁺, Fe³⁺)₂O_3+x, and (Fe²⁺, Fe³⁺, V³⁺)(Fe²⁺, Fe³⁺, V³⁺, Va)₂O₄. Continuous solid solution FeV₂O₄-Fe₃O₄ is formed. The nonstoichiometry of FeV₂O₄ is attributed to the appearance of vanadium vacancies for electroneutrality due to the oxidation of Fe²⁺. The standard Gibbs energy of formation for FeV₂O₄ and component activities in FeV₂O₄-Fe₃O₄ solid solution at 1623 and 1773 K are derived based on the equilibrium oxygen partial pressure. The cation distribution in FeV₂O₄ at different temperatures is obtained according to site preference energy.     

Effect of Fe doping on the magnetic properties of PbPdO2 nanograin film fabricated by sol-gel method

The single-phase Fe-doped PbPdO₂ film was prepared using a sol-gel spin-coating method. The film had a nanograin structure consisting of compacted particles with an average crystallization size of about 35.2 nm. Large amount of Pb vacancies were found in the film. The valences of the Pb, Pd and Fe ions of the film were confirmed to be near 2+, 2+ and 3+, respectively. The additional electron provided by Fe³⁺ and the high ionization energy of Fe³⁺ ensure the stability of the valence of doped Fe ions. The measurement of hysteresis loops and the theoretical fitting of the zero-field-cooled and field-cooled magnetization versus temperature curve indicated that the ferromagnetism and the paramagnetism coexist in the Fe-doped PbPdO₂. And the ferromagnetism persisted up to 380 K. A bound magnetic polaron model based on the Pb vacancies, the carriers and the doped Fe ions was utilized to account for the origin of the film's ferromagnetism. The isolated Fe ions or magnetic polarons were believed to be responsible for the paramagnetism in the film.     

Effects of Sn4+ doping and oxygen vacancy on magnetic and electrical properties of yttrium iron garnet prepared by sol-gel method

Sn-substituted yttrium iron garnet samples, Y₃Fe_5-xSn_xO₁₂ (x = 0–0.1, step 0.02) were prepared using a citrate sol–gel method and followed by a sintering process. Synchrotron X-ray diffraction (SXRD), X-ray absorption near edge structure (XANES), scanning electron microscope (SEM) and Fourier infrared spectroscopy (FTIR) measurements were used to investigate the structure parameters, valence state of Fe, oxygen vacancies and lattice distortion in the samples. The magnetic properties of the samples were measured with the SQUID and VSM equipments. The Sn substitution and oxygen vacancies cause the transformation of Fe³⁺ to Fe²⁺ which leads to the decrease of Curie temperature and slight increase of saturation magnetization. Temperature dependence of the resistivity in the range of 300–573 K was investigated to elucidate the conduction mechanism in the samples. The resistivity of the sol-gel derived samples was found to be nine orders of magnitudes lower than the value for the bulk sample prepared by flux-grown method. The effects of Fe²⁺ centers, lattice dislocation, porosity and grain boundary on the resistivity are discussed. This study indicates that Sn-substituted yttrium iron garnets are good candidates for sensor elements which operate based on electrical signals.     

Size and Lone Pair Effects on the Multiferroic Properties of Bi0.75A0.25FeO3−δ (A = Sr,Pb, and Ba) Ceramics

The work presents a comparative study of the effects of divalent Ba, Sr, and Pb substituents on the multiferroic properties of BiFeO₃. The multiferroic properties of Bi_0.75A_0.25FeO₃ (A = Sr, Pb, Ba) solid solution have been explained taking into account the effects of size differences and electronic configuration differences between the host element (Bi) and the substituent. X‐ray diffraction studies revealed that Sr and Pb substitution at Bi‐site transforms the rhombohedral phase (R3c) to cubic phase (Pm3m), whereas the Ba‐substituted sample exhibited the presence of both rhombohedral and cubic phases (R3c + Pm3m). Electronic structure studies through XPS revealed that charge imbalance induced by divalent substitution was being compensated by the formation of oxygen vacancies, while the Fe ions exist in Fe²⁺ and Fe³⁺ states. Replacement of volatile Bi by Sr, Pb, and Ba reduces the concentration of oxygen vacancies (V_O²⁺) and helps to improve the dielectric properties. Strong magnetization enhancement was observed in the substituted compositions and was seen to be consistent with the suppression of cycloid spin structure due to structural transformation as well as possible changes in Fe–O local environment leading to local lattice distortion effects. Furthermore, the observed decrease in the values of magnetic coercivity at low temperature in all the substituted samples is explained in terms of reduced effective single ion anisotropy, originating in the magnetoelectric coupling and being a particularly stronger effect in the case of the lone pair dopant Pb, consistent with theoretical predictions. The lone pair substituent Pb leads to the largest dielectric constant, enhanced magnetization, and large effects on the low‐temperature hysteresis.     

Multi-doped bismuth ferrite thin films with enhanced multiferroic properties

Thin films of multi-doped bismuth ferrite, Bi_0.97−xLa_xSr_0.03Fe_0·94Mn_0·04Co_0·02O₃ (BL_xSFMC, x = 0.00–0.18), are synthesized on a fluorine-doped tin oxide (FTO)/glass substrate. The structure and multiferroic properties of the film samples are characterized and tested. The results indicate that on doping, the structure of the BL_xSFMC film changes has been changed. The concentrations of both oxygen vacancies and Fe²⁺ are decreased. The BL_0.18SFMC thin film exhibits Ohmic conduction, which reduces the influence of the built-in electric field E_bi of the space-charge region at the interface between an Au electrode and the BL_xSFMC during polarization. The BL_0.18SFMC thin film also exhibits enhanced ferroelectric properties than the undoped film, with a higher residual polarization of 188 μC/cm² and a higher squareness ratio of 1.21. Meanwhile, the reduced number of oxygen vacancies also reduces the Fe²⁺/Fe³⁺ ratio, thereby enhancing the Dzyaloshinskii–Moriya interaction of Fe–O–Fe bonds, and so the BL_0.18SFMC thin film exhibits enhanced ferromagnetism, with a saturation magnetization of M_s ≈ 3.94 emu/cm³. Thus, multi-ion doping can improve both the ferroelectric and ferromagnetic properties of BL_xSFMC thin films.     

Structural,magnetic, and dielectric properties in Aurivillius phase SrxBi6-xFe1-x/2Co1-x/2Ti3+xO18

Sr_xBi_6-xFe_1-x/2Co_1-x/2Ti_3+xO₁₈ (x = 0, 0.25, 0.5, 0.75, 1)(SBFCT-x) ceramics were prepared by the sol-gel auto-combustion method, and their microstructures, ferroelectric, magnetic and dielectric properties were investigated. All samples show layer-perovskited Aurivillius phase, which confirms that Sr doping does not affect the structure of SBFCT ceramics. The coexistence of ferroelectricity and ferromagnetism were observed at room temperature for all the samples. The largest remnant polarization (2P_r ˜ 17.4 μC/cm²) is observed in the SBFCT-1 ceramic, while the SBFCT-0.5 ceramic shows the highest remnant magnetization (2M_r ˜ 0.74 emu/g). To explore the effect of valance states of magnetic ions on the properties, we analysed the content variation of Fe²⁺, Co²⁺, and oxygen vacancies by the X-ray photoelectron spectroscopy results. Furthermore, dielectric anomalies have been found around 400 K, which can be ascribed to the hopping process of oxygen vacancies. The effects of Sr and Ti substitution on ferroelectric and magnetic properties have been investigated and discussed.     

Lychee-like ZnO/ZnFe2O4 core-shell hollow microsphere for improving acetone gas sensing performance

Uniformly lychee-like ZnO/ZnFe₂O₄ core-shell hollow microspheres with average size of 2.5 μm were successfully synthesized via one-step solvothermal self-assembly route. The core-shell hollow microspheres possessed mesoporous structure with a pore size of about 8.8 nm and the large specific surface area of approximately 54.0 m²/g. The effect of the Zn²⁺ concentration on the structure, morphology and gas-sensing property of the as-prepared samples were investigated by a series of testing techniques. The gas-sensing results demonstrated that the sensors based on core-shell ZnO/ZnFe₂O₄ hollow microspheres showed superior gas-sensing response, rapid response-recovery to low-ppm acetone. These excellent properties might be mainly owing to the unique core-shell structure, the large specific surface area, high concentration of oxygen vacancies and the synergetic effect between ZnO and ZnFe₂O₄. Hence, this material can be utilized as promising gas-sensing materials in the acetone detection.     

Antiferromagnetic-ferromagnetic transition in Bi-doped LaFeO3 nanocrystalline ceramics

A series of nanocrystalline La_1-xBi_xFeO₃ (0.0≤x ≤ 0.5) ceramic powders were successfully prepared by the sol-gel method. X-ray diffraction and transmission electron microscopy were used to investigate the crystal structure evolution and hyperfine interactions of the samples. The average diameter of the powders was revealed to be approximately 80 nm. All the samples were crystallized into an orthorhombic crystal structure (space group Pnma) with no second phase. The magnetization of the Bi-doped samples obviously improved with increasing Bi content. A remarkable antiferromagnetic/ferromagnetic transition was detected at x ≥ 0.2, and a high coercive field of 23.05 kÖe was obtained with x = 0.5. The high correlation between the magnetization parameters and bonding characteristics indicated that significant stretching of the Fe³⁺-O_d^2- bonds and a decrease in Fe³⁺-O_d^2--Fe³⁺ linkage angles were the main origins of the strong ferromagnetism in the Bi-doped systems.     

Atomic hydrogenation-induced paramagnetic-ferromagnetic transition in zinc ferrite

A paramagnetic-ferromagnetic transition was observed in normal spinel zinc ferrite (ZnFe₂O₄) during atomic hydrogenation at room temperature. Magnetic measurements showed enhanced ferromagnetic property with increasing hydrogenation time. The hydrogenated ZnFe₂O₄ has normal spinel structure according to X-ray diffraction (XRD) and Raman analyses. Iron hydride was found from the XRD and X-ray absorption fine structure results. No A–B site ions exchange was observed in the x-ray absorption spectra while the atomic distances of Fe–O, Zn–O, Fe–Fe, Zn–Zn and Fe–Zn coordinations were reduced. A hybrid of Fe²⁺ and Fe³⁺ in hydrogenated ZnFe₂O₄ can be further revealed through deconvolution of x-ray absorption near edge structure. The paramagnetic-ferromagnetic transition and enhanced ferromagnetic property were mainly due to the formation of iron hydride and the B-site super-exchange interactions of Fe²⁺ and Fe³⁺.     

Softening-hardening transition of electrical properties for Fe3+-doped (Pb0.94Sr0.05La0.01)(Zr0.53Ti0.47)O3 piezoelectric ceramics

Fe³⁺-doped (Pb_0.94Sr_0.05La_0.01)(Zr_0.53Ti_0.47)O₃ (PSL(ZT)_1-x-Fe_x) piezoelectric ceramics were prepared by the solid-state reaction method and with a variation of the Fe³⁺ content. When the Fe³⁺ content was less than 0.010, the ceramics exhibited the features of soft piezoelectric ceramics with a large remnant polarization (P_r) of 35.7 μC/cm², a large bipolar strain of 0.22% and a high piezoelectric coefficient (d₃₃) of 412 pC/N. The number of oxygen vacancies increased and the domain walls were pinned by the defect diploes with a further increase of the Fe³⁺ content. Meanwhile, the PSL(ZT)_1-x-Fe_x ceramics showed typical hard behavior and the mechanical quality factor Q_m was as high as 500. The softening-hardening transition of electrical properties was also systematically analyzed by adjusting the oxygen vacancies, the space charges and the difference between the unipolar strain and the value of d₃₃×E.     

Mechanism-based tuning of room-temperature ferromagnetism in Mn-doped β-Ga2O3 by annealing atmosphere

Mn-doped β-Ga₂O₃ (GMO) films with room-temperature ferromagnetism (RTFM) are synthesized by polymer-assisted deposition, and the effects of annealing atmosphere (air or pure O₂ gas) on their structures and physical properties are investigated. The characterizations show that the concentrations of vacancy defects and Mn dopants in various valence states and lattice constants of the samples are all modulated by the annealing atmosphere. Notably, the samples annealed in air (GMO–air) exhibit a saturation magnetization as strong as 170% times that of the samples annealed in pure O₂ gas (GMO–O₂), which can be quantitatively explained by oxygen vacancy (V_O)-controlled ferromagnetism due to bound magnetic polarons established between delocalized hydrogenic electrons of V_Os and local magnetic moments of Mn²⁺, Mn³⁺, and Mn⁴⁺ ions in the samples. Our results provide insights into mechanism-based tuning of RTFM in Ga₂O₃ and may be useful for design, fabrication, and application of related spintronic materials.     

Microwave-assisted synthesis of α-Fe2O3/ZnFe2O4/ZnO ternary hybrid nanostructures for photocatalytic applications

Solar-driven highly efficient photocatalytic decomposition of toxic organic contaminants using magnetically separable α-Fe₂O₃/ZnFe₂O₄/ZnO ternary hybrid nanodiscs is reported. α-Fe₂O₃/ZnFe₂O₄/ZnO ternary hybrid nanostructures were synthesized by microwave-assisted co-precipitation and simple co-precipitation methods and well characterized by XRD, micro-Raman, FESEM and UV–vis spectroscopy. FESEM micrographs revealed nanodiscs in case of microwave-assisted co-precipitation whereas nanoparticles and their aggregates were formed under co-precipitation combined with calcination. XRD and Raman studies confirmed the hybrid nature of prepared α-Fe₂O₃/ZnFe₂O₄/ZnO nanostructures. Photocatalytic performance of α-Fe₂O₃/ZnFe₂O₄/ZnO hybrid nanostructures was investigated by carrying out the photodegradation of organic dyes MB and MG under solar light illumination. The prepared α-Fe₂O₃/ZnFe₂O₄/ZnO ternary hybrid magnetic nanodiscs decomposed MB and MG dyes in only 32 and 24 min, respectively. α-Fe₂O₃/ZnFe₂O₄/ZnO hybrid nanodiscs showed excellent photocatalytic performance together with reusability and easy magnetic separation demonstrating its suitability for solar-driven photocatalytic water purification applications. In-situ scavenger studies showed ?OH radicals are the main active radicals in solar-driven photocatalysis by α-Fe₂O₃/ZnFe₂O₄/ZnO nanodiscs. The tentative mechanism of growth of α-Fe₂O₃/ZnFe₂O₄/ZnO ternary hybrid nanodiscs and the photocatalytic mechanism are discussed.     

Hydrothermal synthesis of uniform Fe-doped Gd(OH)3 nanorods and their magnetic properties: Phase conversion from paramagnetism to ferromagnetism

High quality pure and Fe-doped Gd(OH)₃ nanorods were fabricated through a template-free hydrothermal method for the first time. Analysis of XRD indicates that Fe³⁺ was incorporating in the interstitial sites rather than occupying the substitutional sites, forming pure hexagonal structure of Gd(OH)₃ without any other impurity phase. TEM characterizations show that all the samples perform uniform rod-like morphologies with similar diameter and length, which suggests that the Fe doping has little influence on the morphologies of samples. ICP and XPS spectra suggest that the dopant Fe³⁺ is incorporated into the inner body sites, not on the surface of nanorods. Magnetic studies show that the magnetic phase can be converted from paramagnetism to room-temperature ferromagnetism by doping Fe³⁺ ions into the Gd(OH)₃ nanorods. The saturation magnetization (Ms) is sensitive to the amount of Fe dopants, and the Ms for Fe_0.03Gd_0.97(OH)₃ nanorods reaches the maximum value of 0.184 emu/g. It is considered that the ferromagnetic ordering is possibly originated from the exchange interaction of Fe³⁺ through the oxygen vacancies, leading to the formation of point defect-mediated bound magnetic polarons (BMPs). Ruling out the affect of morphologies and secondary magnetic phase on the magnetic properties, the ferromagnetic ordering in uniform Fe-doped Gd(OH)₃ nanorods, in which the dopant Fe³⁺ is incorporated into the inner body sites of nanorods, are of great importance to deeply understand the rare earth-based DMS/DMD systems and have potential applications in spintronic devices.     

Preparation and characterization of spindle-like Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> mesoporous nanoparticles

Magnetic spindle-like Fe₃O₄ mesoporous nanoparticles with a length of 200 nm and diameter of 60 nm were successfully synthesized by reducing the spindle-like α-Fe₂O₃ NPs which were prepared by forced hydrolysis method. The obtained samples were characterized by transmission electron microscopy, powder X-ray diffraction, attenuated total reflection fourier transform infrared spectroscopy, field emission scanning electron microscopy, vibrating sample magnetometer, and nitrogen adsorption-desorption analysis techniques. The results show that α-Fe₂O₃ phase transformed into Fe₃O₄ phase after annealing in hydrogen atmosphere at 350°C. The as-prepared spindle-like Fe₃O₄ mesoporous NPs possess high Brunauer-Emmett-Teller (BET) surface area up to ca. 7.9 m² g^-1. In addition, the Fe₃O₄ NPs present higher saturation magnetization (85.2 emu g^-1) and excellent magnetic response behaviors, which have great potential applications in magnetic separation technology.     

Structure-activity Relation of Fe2O3–CeO2 Composite Catalysts in CO Oxidation

A series of Fe₂O₃–CeO₂ composite catalysts were synthesized by coprecipitation and characterized by X-ray diffraction (XRD), BET surface area measurement, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Their catalytic activities in CO oxidation were also tested. The Fe₂O₃–CeO₂ composites with an Fe molar percentage below 0.3 form solid solutions with the CeO₂ cubic fluorite structure, in which the doped Fe³⁺ initially substitutes Ce⁴⁺ in fluorite cubic CeO₂, but then mostly locate in the interstitial sites after a critical concentration of doped Fe³⁺. With an Fe molar percentage between 0.3 and 0.95, the Fe₂O₃–CeO₂ composites are mixed oxides of the cubic fluorite CeO₂ solid solution and the hematite Fe₂O₃. XPS results indicate that CeO₂ is enriched in the surface region of Fe₂O₃–CeO₂ composites. The Fe₂O₃–CeO₂ composites have much higher catalytic activities in CO oxidation than the individual pure CeO₂ and Fe₂O₃, and the Fe_0.1Ce_0.9 composite shows the best catalytic performance. The structure-activity relation of the Fe₂O₃–CeO₂ composites in CO oxidation is discussed in terms of the formation of solid solution and surface oxygen vacancies. Our results demonstrate a proportional relation between the catalytic activity of cubic CeO₂-like solid solutions and their density of oxygen vacancies, which directly proves the formation of oxygen vacancies as the key step in CO oxidation over oxide catalysts.     

Multifunctional behavior of acceptor-cation substitution at higher doping concentration in PZT ceramics

The Fe-doped PZT, Pb (Zr, Ti)_1-xFe_xO₃, ceramics have gathered plenty of attention because of the interplay of ferroelectric and ferromagnetic properties. In the present study, we report the properties of Pb(Zr_0.52Ti_0.48)_1-xFe_xO₃ prepared by conventional solid-state reaction route with varying Fe³⁺ doping concentrations, x = 0, 0.05, 0.10, 0.15 and 0.20. Study of X-ray diffraction patterns confirmed the tetragonal crystal structure along with reduction in tetragonality and unit-cell size with doping. It also showed formation of secondary magneto-plumbite phase at higher doping concentrations. The SEM micrographs exhibited decrease in grain size with increase in doping concentration (for x > 0.05). The increase in oxygen vacancies and the formation of secondary magneto-plumbite phase and Fe³⁺–VO²⁻–Fe³⁺ defect dipole complexes introduced with the acceptor (Fe³⁺) doping, caused clamping of the domain walls and hence reduced the room temperature dielectric constant as the doping concentration was increased. The coexistence of electrical polarization and magnetic moment at room temperature in all PFZT compositions confirmed the multiferroic characteristic in the ceramic samples. Electric polarization (P_r) and coercive fields (E_c) decreased with increase in Fe³⁺ concentration in PFZT sample. However, magnetization (M) and magnetic coercive fields (E_c) increased with the increasing Fe³⁺ concentration due to the dominant effect of F-center exchange mechanism in Fe³⁺–VO²⁻–Fe³⁺ and formation of ferromagnetic secondary magneto-plumbite phase.     

Structural development and magnetic phenomenon in Zn–Cr–Fe multi oxide nano-crystals

The Cr³⁺ ions doped multi-oxide ZnFe_2−xCr_xO₄ ferrite nanoparticles have been synthesized by chemical co-precipitation method. Site occupancies of Zn²⁺, Cr³⁺ and Fe³⁺ ions were analyzed using X-ray diffraction data and Buerger's method. The effect of the constituent phase variation on the magnetic hysteresis behavior was examined by saturation magnetization which decreases with the increase in Cr³⁺ content in place of Fe³⁺ ions at octahedral B-site. Typical blocking temperature (T_B) around 90 K was observed by zero field cooling and field cooling magnetization study. Room temperature Mössbauer spectra show two paramagnetic doublets (tetrahedral and octahedral sites). The isomer shifts of both doublets decrease whereas quadrupole splitting and relative area of tetrahedral A-site increases with increasing Cr³⁺ substitution. The dielectric constant (measured on compositions x=0, 0.4, 0.8 and 1.0) increases when the temperature increases as in the semiconductor. This behavior is attributed to the hopping of electrons between Fe²⁺ and Fe³⁺ ions with a thermal activation.     

Preparation of magnetic α-Fe2O3/ZnFe2O4@Ti3C2 MXene with excellent photocatalytic performance

The high conductivity Ti₃C₂ MXene with the unique lamellar nanostructure can effectively improve photoelectrocatalytic ability of composite as cocatalyst. In this paper, the magnetic α-Fe₂O₃/ZnFe₂O₄ heterojunctions were obtained using one-step hydrothermal synthesis. And α-Fe₂O₃/ZnFe₂O₄@Ti₃C₂ MXene photocatalyst can be easily obtained by ultrasonic assisted self-assembly approach for dispersing magnetic α-Fe₂O₃/ZnFe₂O₄ heterojunctions on Ti₃C₂ MXene surface. Due to the improving photoelectron ability, the α-Fe₂O₃/ZnFe₂O₄@Ti₃C₂ MXene was found to exhibit the higher photocatalytic ability than the α-Fe₂O₃/ZnFe₂O₄ heterojunctions in eliminating Rhodamine B (RhB) pollutant and toxic Cr(Ⅵ) in water. Even more important, as a magnetic composite, the 10 wt% α-Fe₂O₃/ZnFe₂O₄@Ti₃C₂ MXene photocatalyst exhibited the excellent reusability. The terrific photocatalytic ability is due to the numerous heterostructure interfaces, the increase of visible light harvesting and high conductivity.