Spinel Cu1 Research Articles

Mutual effects of CO and benzene oxidation over Cu catalysts: The role of surface oxygen species and reaction pathways

CuMn, CuMnCe, and CuCe metal oxide catalysts were prepared and applied in oxidizing CO and benzene as representative volatile organic compounds (VOCs). Various characterization methods and in situ diffuse reflectance infrared Fourier transform spectra (DRIFTS) were used to explore mutual effects between CO and benzene oxidation and the role of reactive oxygen species. CuMn shows the highest activity in independent and simultaneous oxidation of CO and benzene due to its spinel Cu1.5Mn1.5O4 structure, which gives abundant Cu+ sites, acidic sites, Oα, and Oβ. Cu+ sites and Oα benefit CO oxidation, while acidic sites, Oα, and Oβ contribute to benzene oxidation, producing intermediates decomposable at low temperatures. Mechanism study reveals that benzene inhibits CO oxidation by competing for Oα at low temperatures to retard carbonate intermediates formation. CO enhances benzene oxidation by promoting benzene preliminary oxidation and intermediates deep degradation. On CuMn, the formation and degradation of maleate and acetate are facilitated, while maleate and formate degradation are promoted on CuMnCe and CuCe, respectively.

Phytotoxic and electrochemical properties of mixed Cu-Ni cobaltite nanoflowers: Environmental and energy storage applications

Herein, the flower-like mixed Cu-Ni cobaltite spinels Cu1−xNixCo2O4 (x = 0, 0.05, 0.15, and 0.25) were successfully synthesized via simple hydrothermal approach followed by annealing process. Copper cobaltite flowers were characterized using XPS, XRD, FT-IR, SEM, TEM, EDAX, BET, and UV–Vis analysis. The photodegradation efficiency (PDE) of the cobaltite photocatalysts was determined by the degradation of rhodamine 6 G (Rh6G), methylene green (MG), and mixed dye effluents (Rh6G+MG, 1:1 v/v) upon visible-light radiation. The PDE of the CNC 3 catalyst was found to be 90%, 83%, and 86% for degradation of Rh6G, MG, and mixed dye effluents, respectively, and it retained 87% of photocatalytic efficiency even after four cycles. The phytotoxic analysis of control, untreated, and treated Rh6G dye solutions was examined in Phaseolus vulgaris for real-time applications. The electrochemical characteristic was investigated by CV, GCD, and EIS. The CNC 3 electrode showed excellent electrochemical performance (315 Fg−1 at 0.5 Ag−1), and the capacity reached 93% of its initial capacitance after 3000 cycles. The b values of oxidative and reductive currents were determined to be 0.67 and 0.68, respectively. The capacitance contribution was 56% at 10 mVs−1, indicating a mixture of surface capacitive and diffusion controlled behavior in charge/discharge processes. The two-electrode symmetric cell was fabricated using CNC 3 as the positive and negative electrodes for real-life applications. CNC 3 cell delivered a significant energy density (13.47 Wh/kg) and a power density (251.01 W/kg) at 0.5 Ag−1.

Low-temperature catalytic performance of toluene oxidation over Cu-Mn oxide catalysts derived from LDH precursor

A series of CuMn mixed oxides catalysts (CMO-T) were prepared by calcination of CuMn layered double hydroxides (CuMn-LDH) for catalytic oxidation of toluene. The obtained CMO-400 catalyst exhibited a high catalytic activity with T50 and T90 of 210 and 231 °C (WHSV = 30000 mL·g−1·h−1). Meanwhile, the CMO-400 exhibited high stability and durability even at 20 vol% water vapor. The effects of calcination temperature on the texture and structural properties were investigated systematically, which proved the formation of copper-manganese solid solution with abundant multiple-phase interfaces. In addition, the strong interaction between Cu and Mn could lead to more surface adsorbed oxygen due to oxidation reduction cycle of Mn3++Cu2+=Mn4++Cu+. Accordingly, for CMO-500 catalyst, the formation of spinel Cu1.5Mn1.5O4 phase prevented good dispersion of the manganese-oxide phases and weakened the reducibility and oxygen mobility. In-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) revealed that the intermediates accumulated continuously were difficult to be oxidized rapidly without the replenishment gaseous oxygen. Moreover, the complete transformation of the intermediate benzoate may be the key rate-controlling step in the reaction. The Facile method of preparing mixed-metal solid solution from LDH precursor system could be widely developed for the design of transition metals in catalytic oxidation of toluene.

The formation of spinel CuxMn3-xO4 at 750 °C in the designed CuMn layers for solid oxide fuel cell applications

The Cu-Mn based spinel coatings without Cr show good application prospects due to their high conductivity and thermal expansion coefficient matching with metallic interconnectors. Based on the Cu-Mn-O phase diagram, the CuMn alloy layers with different Cu/Mn ratios were designed by electro-deposition and high energy micro-arc alloying (HEMAA) processes. The Mn-33Cu-17Co layer was prepared by HEMAA for thermal growth of the CuMn spinel oxides, and the fine-grained 430 layer was prepared by HEMAA as an interlayer at the interface between the 430 SS substrate and the coating. The microstructure and composition of the composite layers were analyzed. The results show that after oxidation treatment at 750 °C for 500 h, the oxide products of the Mn-33Cu-17Co layer were mainly cubic spinel Cu1.4Mn1.6O4 and CuO, which were different from those of the Mn-35Cu oxide layer, spinel Cu1.2Mn1.8O4 and Mn2O3. The aggregation of Cu-rich oxides was not found in the cross-section and on the top surface of the Mn-33Cu-17Co oxide layer, and the outer spinel layer was uniform and compact. The designed Mn-33Cu-17Co layers, Mn-35Cu layers and Mn1.5Cu1.5 layers showed good high temperature oxidation resistance and electrical conductivity.

Fabrication of Cu1.5Mn1.5O4 Nanoparticles Using One Step Self-Assembling Route to Enhance Energy Consumption

The preparation of copper manganite (hopcalite, Cu1.5Mn1.5O4), as a single phase, was achieved by using a sustainable method of green synthesis. This method is based on the replacement of the conventional “brute force” ceramic preparation by the recent “soft force” green synthesis via the egg white assisted one-step method. In other words, we present a facile and rapid methodology to prepare the nanocrystalline Cu1.5Mn1.5O4 spinel as a single phase, compared to our previous work using ceramic and glycine-assisted combustion methods. The as-synthesized copper manganite was characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR), energy-dispersive spectroscopy (EDS), and scanning electron microscope (SEM). We used a vibrating sample magnetometer to determine the magnetic properties of the prepared sample (VSM). XRD, FTIR, SEM, EDS and transmittance electron micrograph (TEM) resulted in synthesis of a successful cubic spinel Cu1.5Mn1.5O4 system with a sponge crystal structure. The particles of the prepared materials are polycrystalline in their nature and the sizes ranged between 50 and 100 nm. The magnetic measurement demonstrated that the generated nanostructure has been found to exhibit ferromagnetism at room temperature with an optimum saturation magnetization value (0.2944 emu/g).

Study of physical properties of a ferrimagnetic spinel Cu1.5Mn1.5O4: spin dynamics, magnetocaloric effect and critical behavior.

The present work reports a detailed study of the spin dynamics, magnetocaloric effect and critical behaviour near the magnetic phase transition temperature, of a ferrimagnetic spinel Cu1.5Mn1.5O4. The dynamic magnetic properties investigated using frequency-dependent ac magnetic susceptibility fitted using different phenomenological models such as Neel–Arrhenius, Vogel–Fulcher and power law, strongly indicate the presence of a cluster-glass-like behavior of Cu1.5Mn1.5O4 at 40 K. The magnetization data have revealed that our compound displays an occurrence of second-order paramagnetic (PM) to ferrimagnetic (FIM) phase transition at the Curie temperature TC = 80 K as the temperature decrease. In addition, the magnetic entropy change (ΔSM) was calculated using two different methods: Maxwell relations and Landau theory. An acceptable agreement was found between both sets of data, which proves the importance of both electron interaction and magnetoelastic coupling in the magnetocaloric effect (MCE) properties of Cu1.5Mn1.5O4. The relative cooling power (RCP) reaches 180.13 (J kg−1) for an applied field at 5 T, making our compound an effective candidate for magnetic refrigeration applications. The critical exponents β, γ and δ as well as transition temperature TC were extracted from various techniques indicating that the magnetic interaction in our sample follows the 3D-Ising model. The validity of the critical exponents is confirmed by applying the Windom scaling hypothesis.

Highly efficient copper-manganese oxide catalysts with abundant surface vacancies for low-temperature water-gas shift reaction

Efficient and low-cost water-gas shift (WGS) catalysts have aroused much attention for the purification of H2-rich syngas in the application of fuel cell. In this study, combustion of ethylene glycol and methanol (EGM), fractional precipitation (FP) and template growth (TG) methods have been utilized to synthesize copper-manganese oxide (CMO) catalysts. The prepared CMO catalysts are consisted of spinel Cu1.5Mn1.5O4 and Mn2O3 phases and exhibit porous, polyhedral nanoparticle and nanorod morphologies for EGM, FP and TG, respectively. The low-temperature WGS reaction activities of prepared catalysts follow the sequence: CMO-EGM > CMO-FP > CMO-TG, which are higher than that of CMO catalyst prepared by traditional co-precipitation method. Among them, CMO-EGM catalyst exhibits the highest reaction rate of 122.72 μmolCO gcat.−1 s−1 at 200 °C, which is much higher than that of commercial Cu/ZnO/Al2O3 (73.62 μmolCO gcat.−1 s−1). CO-TPSR and DRIFTS analysis reveal the superior activity of CMO-EGM is attributed to the larger amounts of active hydroxyl groups on the surface of catalysts, which correlate well with the high reducibility and abundant surface oxygen vacancies of CMO-EGM catalyst.

Preparation of ultrafine Cu1.5Mn1.5O4 spinel nanoparticles and its application in p-nitrophenol reduction

In this work, ultrafine Cu1.5Mn1.5O4 spinel nanoparticles were successfully synthesized by a sol–gel method combined with two complexing agents, which was firstly employed in the reductive transformation from p-nitrophenol into p-aminophenol. The effect of calcination temperature on the crystal phase and microstructure of Cu1.5Mn1.5O4 nanoparticles was investigated in this article. It was found that Cu1.5Mn1.5O4 nanoparticles with pure spinel phase can be obtained at 500 °C with the help of EDTA acid–citric acid complexing agents. Below 500 °C, there exists some Mn2O3 impure phase. SEM characterization indicated that the particle size of the spinel Cu1.5Mn1.5O4 rapidly increases above 600 °C. The catalytic experimental results show that the Cu1.5Mn1.5O4 nanoparticles prepared at 500 °C exhibit the highest catalytic activity which is even superior to some precious metal catalysts. With the calcination temperature increasing, the catalytic activity of Cu1.5Mn1.5O4 spinel nanoparticles gradually degrades which can be ascribed to the particle size growth of Cu1.5Mn1.5O4. It can also be observed that all the oxide samples, namely CuO, Mn2O3 and Cu1.5Mn1.5O4, possess certain catalytic ability for the transformation from p-nitrophenol into p-aminophenol. However, the catalytic activity of Cu1.5Mn1.5O4 spinel nanoparticles is obviously higher than CuO and Mn2O3. Especially, Mn2O3 alone has very poor catalytic activity in the reduction of p-nitrophenol.

Aqueous solution-chemical derived spinel Cu1.5Mn1.5O4 thin film for solar absorber application

Spinel Cu1.5Mn1.5O4 thin films were fabricated by one step sol-gel dip-coating method using aqueous solution. The effect of deposition parameters on thickness, surface feature, and optical property of thin films was systematically studied. The results revealed that the increased withdrawal speeds and high concentration of metal ions in precursor were conducive to obtaining thicker films which exhibited excellent solar absorptance. Furthermore, the surface feature derived from the different concentrations of metal ions had a significant effect on optical behavior of the thin film. Consequently, excellent spectral selectivity of the thin film would be achieved by tuning those deposition parameters.

Copper-manganese-zinc spinels in zeolites: study of EMR spectra

Abstract The aim of this study is the application of electron magnetic resonance (EMR) spectroscopy to determine the interactions between NaY and HY zeolites and Cu-Mn-Zn spinels loaded onto the zeolite surfaces. The materials were characterized using XRD and IR spectroscopies. Four types of EMR lines were observed for Cu-Mn-Zn/NaY, Cu-Mn-Zn/HY samples. The difference between the EMR spectra recorded at 77 and 293 K has been shown. The spectra recorded at 77 K allowed us to distinguish between the species formed on NaY and HY zeolites. The EMR spectrum of Cu-Mn-Zn/NaY recorded at 77 K showed only one line attributed to antiferromagnetic spinels Cu1.4Mn1.6O4 and ZnMn2O4 or/and Cu0.5Zn0.5Mn2O4. The spinels appeared to be more stable (more strongly attached) on HY zeolite than on NaY one. It was proved that different strength of interactions between the zeolites and Cu-Mn-Zn spinels was caused by differences in the acidity of NaY and HY zeolites.

Room Temperature Ferromagnetism of Magnetically Recyclable Photocatalyst of Cu1−x Mn x Fe2O4-TiO2 (0.0 ≤ x ≤ 0.5) Nanocomposites

Magnetically recyclable spinel Cu1−xMnxFe2O4 (0.0 ≤ x ≤ 0.5) ferrite nanophotocatalysts were synthesized by a simple one-pot microwave combustion method using glycine as the fuel. The synthesis process only took a few minutes to obtain CuFe2O4 nanopowders. The formation of nanocrystalline single-phase cubic spinel structure was confirmed by powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR), energy dispersive X-ray (EDX) and selected area electron diffraction pattern (SAED) analyses. The surface morphology of the samples consists of nearly spherical shaped nanoparticles (NPs) with agglomeration, which was confirmed by high-resolution scanning electron microscopy (HR-SEM) and high resolution transmission electron microscope (HR-TEM) analyses. The optical band gap energy (E g) was confirmed by UV-Vis diffuse reflectance spectrum (DRS) study, and the E g of undoped CuFe2O4 sample is 2.39 eV and it is increased from 2.51–2.81 eV with increasing the amount of Mn2+ content (x = 0.1–0.5), due to the decrease of particle size. The magnetic hysteresis (M– H) curve showed ferromagnetic behavior for all compositions. The magnetization (M s) of the samples monotonically increased with increasing Mn content x = 0.0–0.5. Smaller values of coercivity showed soft magnetic nature of Cu1−xMnxFe2O4 NPs. The photocatalytic degradation (PCD) of 4-chlorophenol (4-CP) under visible light using the spinel CuFe2O4 catalysts shows poor activity. Therefore, the present study leads to enhance the photocatalytic (PC) activity of spinel Cu1−xMnxFe2O4 NPs with the addition of TiO2 catalyst using the PCD of 4-CP under visible light. It was found that the coupled Cu1−xMnxFe2O4-TiO2 nanocomposite (NCs) photocatalysts exhibit excellent PC activity than that of Cu1−xMnxFe2O4 and TiO2 catalysts. The sample Cu0.5Mn0.5Fe2O4-TiO2 NCs showed greater performance than the other NCs. The enhanced PC ability of Cu1−xMnxFe2O4-TiO2 NCs could be ascribed to the interconnected heterojunction of spinel Cu1−xMnxFe2O4 and TiO2 catalysts.

Interplay of bulk and surface on the magnetic properties of low temperature synthesized nanocrystalline cubic Cu1−xZnxFe2O4 (x=0.00, 0.02, 0.04 and 0.08)

Synthesis of Cu1−xZnxFe2O4, (x=0.00, 0.02, 0.04 and 0.08) nanoparticles by a low-temperature combustion method is achieved and its structural and magnetic characterizations are performed. X-ray powder diffraction (XRD) study and high resolution transmission electron microscope (HRTEM) images confirm the formation of single cubic phase of nanocrystalline copper ferrite. The inter-planar spacing (d) and particle size increases with increasing Zn content. Cation distribution of mixed spinel Cu1−xZnxFe2O4 nanoparticles are estimated by Fourier transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and further verified by 57Fe Mo¨ssbauer spectroscopy. Detailed magnetic properties are studied by means of Field Cooled (FC) – Zero Field Cooled (ZFC) magnetization measurements and hysteresis loops at various temperatures by the physical property measurement system (PPMS). A transition from superparamagnetic state to ferrimagnetic state is observed as the Zn concentration increases in Cu1−xZnxFe2O4 nanoparticles. The temperature dependence of intrinsic magnetic parameters, i.e., coercivity (HC), saturation magnetization (MS), effective anisotropy constant (Keff) and paramagnetic susceptibility (χp) of Cu1−xZnxFe2O4 reveals the existence of low-temperature spin-glass-like state, which is more prominent for smaller particles and starts to disappear with increasing Zn concentration.

New synthesis of nanosized Cu–Mn spinels as efficient oxidation catalysts

Copper manganese nanoscale oxides were prepared using a novel method with low cost natural biopolymer precursor, alginate, and their catalytic activity was evaluated for the complete oxidation of toluene as a model VOC. Depending on the Cu/Mn ratio the following oxides were formed: Mn3O4, Cu1.5Mn1.5O4, CuO or a mixture of these phases, as detected by XRD. The nanocrystals aggregate in small spheres (≲1mm), which retain the shape of the parent gel and present homogeneous composition as characterized by TEM and SEM-EDX. The best performance for toluene combustion was observed for the cubic spinel Cu1.5Mn1.5O4 nanoparticles (∼10nm), which was able to completely oxidize toluene at ∼240°C. For the pure oxides the activity order: Cu1.5Mn1.5O4>Mn3O4>CuO, correlates with the TPR results as the catalyst with the higher redox potential shows higher activity. For comparison the TiO2 supported oxides were also studied and alginate issued Cu1.5Mn1.5O4 mixed with TiO2 presented similar activity as the Cu–Mn oxide deposited on TiO2 by incipient wetness impregnation however the overall activity of supported oxides was lower than for the unsupported Cu1.5Mn1.5O4. The method used for the synthesis of copper manganite has great potential as it can be extended to other manganite spinels of general formula AMn2O4 and presents the advantage of easy catalyst forming.

The choice of precipitant and precursor in the co-precipitation synthesis of copper manganese oxide for maximizing carbon monoxide oxidation

Copper manganese oxides (CMOs) were synthesized using a co-precipitation method with different precursors and precipitants for carbon monoxide oxidation. The as-synthesized catalysts were characterized by powder X-ray diffraction (XRD), low temperature N2 sorption, Fourier transform-infrared spectroscopy (FT-IR), H2-temperature programmed reduction (H2-TPR), and thermal gravimetric analysis (TGA). Their catalytic activities for CO oxidation were tested by temperature programmed reaction. The results showed that the activity of CO oxidation strongly depended on the combination of precipitant and precursor anions, ranking in the order (Ac−+CO32−)>(NO3−+CO32−)>(Ac−+OH−)>(NO3−+OH−). The crystalline phase of copper manganese oxides obtained using strong electrolyte (OH−) as the precipitant were mainly spinel Cu1.5Mn1.5O4, while the catalysts prepared with weak electrolyte (CO32−) as the precipitant mostly comprised of MnCO3, Mn2O3 and CuO, and showed a much higher CO oxidation activity than that of the Cu1.5Mn1.5O4. Keeping the same precipitant while changing the precursor caused a change in the H2 consumption which influenced the CO oxidation activity. A suitable combination of precipitant and precursor resulted in the most efficient CO oxidation catalyst.

The exchange biaslike effect in tetrahedral spinels Cu1−xZnxCr2O4(x=0.1,0.3)

Exchange biaslike phenomenon is observed in the Zn doped spinel polycrystalline CuCr2O4. The magnetic hysteresis loop shifts in both horizontal and vertical directions at 5 K after the samples are cooled down to 5 K in a magnetic field. The nature of this magnetic anisotropy arises from the freezing properties of the local anisotropy in the cluster glass system. The magnetic shifts along both directions can be observed directly under the principle that the spins of a cluster are frozen in random orientations upon zero field, and aligned to the field direction upon field cooling.

Nickel substituted copper chromite spinels: Preparation, characterization and catalytic activity in the oxidation reaction of ethylbenzene

Nickel substituted copper chromite spinels (Cu1−xNixCr2O4, where x = 0, 0.25, 0.5, 0.75 and 1.0) were prepared by homogeneous co-precipitation method. The materials were characterized in detail by X-ray diffraction, BET surface area, scanning electron microscopy, energy dispersive X-ray analysis and FTIR spectroscopy. Powder X-ray diffraction pattern reveals the spinel phase formation and energy dispersive X-ray analysis indicates the correct stoichiometry. Liquid-phase oxidation of ethylbenzene using TBHP (70%) as an oxidant shows that the catalysts are highly active. Leaching studies performed by hot filtration experiments and reusability studies show that nickel substituted copper chromite spinels are stable under the reaction conditions.

Model of phase transitions in a copper spinel on alloying with antimony

A theoretical study of the properties of the copper spinel Cu1+[Cr1+x3+Cr1−2x4+Sbx5+]S42− is carried out in the framework of the spin Hamiltonian. Only the cation sublattice B, containing the ions Cr3+ (S3=3∕2), Cr4+ (S4=1) and the diamagnetic sites Sb5+ (S=0), is considered. Nearest magnetic ions are coupled by effective exchange interactions via the intermediate anions: J34>0 (double exchange), J44>0, J33<0 (superexchange), where J34≫∣J33∣,J44. For a random distribution of ions the general physical behavior pattern of the system as a function of the concentration x of the alloying element is as follows. In the region x≤xcr≈0.3 there exists an infinite ferromagnetic cluster of intercoupled ionsCr3+–Cr4+ (percolation via strong 3–4 ferromagnetic bonds). At x>xcr finite ferromagnetic clusters appear, oriented “up” and “down” and coupled by antiferromagnetic bonds J33. The total magnetization vanishes, and a spin separation or a state of the cluster spin-glass type is realized. At x→0.5 percolation via antiferromagnetic bonds J33 appears, and practically only simple isolated ferromagnet clusters in an antiferromagnetic matrix remain, oriented “up” and “down” in equal numbers. The limit compound (x=0.5) consists 1/4 of “holes”—diamagnetic sites with broken bonds—and 3/4 of Cr3+ cations with antiferromagnetic bonds. Percolation via 3–4 bonds leads not only to ferromagnetism but also simultaneously to a metallic state owing to the double-exchange mechanism (the formation of a ferromagnetic half metal). In the absence of percolation via 3–4 bonds the system is an insulator. Thus as the copper spinel is alloyed with antimony (0≤x≤0.5), concentration phase transitions occur: a metallic ferromagnet (x<xcr) is transformed to an insulator with spin separation (xcr≈0.3), which in the limit x=0.5 becomes an antiferromagnetic insulator.

Crystallographic and low frequency conductivity studies of the spinel systems CuFe2O4 and Cu1−x Zn x Ga0.1Fe1.9O4; (0.0 ≤ x ≤ 0.5)

Spinel solid solutions of CuFe2O4 and Cu1−x Zn x Ga0.1Fe1.9O4 with (0.0 ≤ x ≤ 0.5) are synthesized. Crystallographic phase transformation from tetragonal-to-cubic occurred at x = 0.2. The derived structural parameters manifest that Zn occupies the tetrahedral A-site while Cu and Ga occupy the octahedral B-site and Fe distributes among A- and B-sites. Electrical conductivity measurements of these materials as a function of temperature and frequency revealed semiconducting behavior except CuFe2O4 sample, which has a metallic behavior at low frequency and at high frequency, semiconductor-to-metallic transition occurred as temperature increases. The metallic behavior in this sample is attributed to cation-cation interactions at B-site while, the semiconductor behavior in Cu1−x Zn x Ga0.1Fe1.9O4 compounds is due to the cation–anion–cation interactions at the same site in the spinel lattice. All compositions exhibit transition with change in the slope of conductivity versus temperature curve. This transition temperature (T c) decreases linearly with increasing Zn content x. The relation of the universal exponent s with temperature gives evidence that over large polaron OLP and correlated barrier hopping CBH conduction mechanisms are presented in CuFe2O4 and Cu1−x Zn x Ga0.1Fe1.9O4 compounds respectively.

X-ray, IR and bulk magnetic properties of Cu1 + xMnxFe2–2xO4 ferrite system

The structural, IR and magnetic properties of the mixed spinel Cu1 + xMnxFe2-2xO4 (x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6) system have been investigated by means of X-ray diffraction, Infrared spectroscopy, magnetization and a.c. susceptibility measurements. X-ray results confirm single-phase spinel structure for all the concentrations. The structure of CuFe2O4 is tetragonal and changes to cubic for x = 0.1 to 0.4. For x = 0.5 and 0.6 the structure become tetragonal. The lattice parameter and X-ray density are deduced and their variation with Mn4+ concentration is studied. The cation distribution derived from the X-ray diffractometry data was found to agree very well with the cation distribution obtained from magnetization measurements. X-ray intensity calculations indicate that Mn4+ occupy only octahedral [B] sites and Cu2+ and Fe3+ ions occupy both octahedral [B] and tetrahedral (A) sites. The infrared spectra obtained at room temperature in the range 200–800 cm−1 showed two absorption bands. The force constants have been obtained from IR data. The variation of the saturation magnetization per formula unit as a function of Mn4+ content x has been satisfactorily explained on the basis of Neel's collinear spin ordering model for all values of x. The Curie temperature TC determined from a.c. susceptibility data decreases with increase of Mn4+ concentration x, suggesting decrease in ferrimagnetic behaviour.