Porous CoFe2O4 Research Articles

Integrating g-C3N4 nanosheets with MOF-derived porous CoFe2O4 to form an S-scheme heterojunction for efficient pollutant degradation via the synergy of photocatalysis and peroxymonosulfate activation

When confronted with wastewater that is characterized by complex composition, stable molecular structure, and high concentration, relying solely on photocatalytic technology proves inadequate in achieving satisfactory degradation results. Therefore, the integration of other highly efficient degradation techniques has emerged as a viable approach to address this challenge. Herein, a novel strategy was employed whereby the exfoliated g-C3N4 nanosheets (CNs) with exceptional photocatalytic performance, were intimately combined with porous rod-shaped cobalt ferrite (CFO) through a co-calcination process to form the composite CFO/CNs, which exhibited remarkable efficacy in the degradation of various organic pollutants through the combination of photocatalysis and Fenton-like process synergistically, exemplified by the representative case of tetracycline hydrochloride (TCH, 200 mL, 50 mg/L). Specifically, under 1 mM of peroxymonosulfate (PMS) and illumination conditions, 50 mg of 1CFO/9CNs achieved a TCH removal ratio of ∼90% after 60 min of treatment. Furthermore, this work comprehensively investigated the influence of various factors, including catalyst and PMS dosages, solution pH, and the presence of anions and humate, on the degradation efficiency of pollutants. Besides, quenching experiments and EPR tests confirmed the establishment of an S-scheme heterojunction between CNs and CFO, which facilitated the effective spatial separation of photoexcited charge carriers and preserved the potent redox potential of photogenerated electrons and holes. This work offers a valuable reference for the integration of photocatalysis with the PMS-based Fenton-like process.

Multi-Pleated Alkalized Ti3 C2 Tx MXene-Based Sandwich-Like Structure Composite Nanofibers for High-Performance Sodium/Lithium Storage.

The volume expansion of CoFe2 O4 anode poses a significant challenge in the commercial application of lithium/sodium-ion batteries (LIBs/SIBs). However, metal-organic-frameworks (MOF) offer superior construction of heterostructures with refined interfacial interactions and lower ion diffusion barriers in Li/Na storage. In this study, the CoFe2 O4 @carbon nanofibers derived from MOF are produced through electrospinning, in situ growth followed by calcination, which are then confined within an MXene-confined MOF-derived porous CoFe2 O4 @carbon composite architecture under alkali treatment. The CoFe2 O4 nanofibers anchor on the alkalized MXene that is decorated with the NaOH solution to form a multi-pleated structure. The sandwich-like structure of the composite effectively alleviates the volume expansion and shortens the Li/Na-ion diffusion path, which displays high capacity and outstanding rate performance as anode materials for LIBs/SIBs. As a consequence, the obtained CoFe2 O4 @carbon@alkalized MXene composite anode shows satisfied rate performance at current density of 10 A g-1 for LIBs (318 mAh·g-1 ) and 5 A g-1 for SIBs (149mAhg-1 ). The excellent cycling performance is further demonstrated at a high current density, where it maintains a discharge capacity of 807 mAh g-1 at 2 A g-1 after 400 cycles for LIBs and 130 mAh g-1 at 1 A g-1 even after 1000 cycles for SIBs.

Bimetal-organic framework-derived porous CoFe2O4 nanoparticles as biocompatible anode electrocatalysts for improving the power generation of microbial fuel cells

HypothesisThe relatively lower power density of Microbial fuel cells (MFCs), primarily resulting from weak biofilm habitation and sluggish extracellular electron transfer (EET) at the anode interface, limits their practical implementation on a large scale. To address this challenge, porous CoFe2O4 nanoparticles could be used as anode electrocatalysts based on the following considerations: (i) the introduction of CoFe2O4 nanoparticles endows the anode with a rough surface that facilitates biofilm formation; (ii) the positively charged Co and Fe ions improve the interfacial affinity of anodes, enabling rapid immobilization and colonization of negatively bacteria; (iii) the multi-valent metal states of Co and Fe can function as electron shuttles, mediating EET process between biofilm and anode. ExperimentsCoFe2O4 nanoparticles prepared with a bimetal-organic framework (B-MOF) as precursor, were modified to the surface of carbon cloth as the anode of MFCs. FindingsMFCs equipped with CoFe2O4 anode achieved a maximum power density of 1026.68 mW m−2, which was approximately 3.4 times higher than that of the pristine carbon cloth. Additionally, the biofilm density and viability on the anode were enhanced after CoFe2O4 modification. Considering the facile fabrication process and superior electrocatalytic performance, the CoFe2O4 nanoparticles are promising electrocatalysts for high performance and cost-effective MFCs.

Porous CoFe2O4 nanorods: VOC gas-sensing characteristics and DFT calculation

Gas-sensing properties of metal oxide are strongly dependent on the morphology, porosity, and crystal size; thus, researchers are trying to improve the sensitivity by using nanomaterials. This study synthesized porous CoFe2O4 (CFO) nanorods with large specific surface area and fine crystal size for volatile organic compounds (VOCs) gas sensor application. The porous CFO nanorods were synthesized by a simple hydrothermal method and subsequent calcination at high temperatures. Results pointed out that the single-phase porous CFO nanorods with diameter and length of ∼500 and ∼4 µm, respectively, were obtained. The nanorod has a porous structure, with a pore size of ∼100 nm, formed from interconnected nanocrystals of an average crystal size of ∼18 nm. The porous CFO nanorods showed the best response to acetone at 350 °C and were suitable for practical application. The adsorption trend (adsorption energy and charge transfer between adsorbent and molecules) is also clarified by the nonempirical van der Waals density functional theory calculation.

High-efficiency adsorption removal of CR and MG dyes using AlOOH fibers embedded with porous CoFe2O4 nanoparticles

Owing to the toxicity and difficulty in degradation, how to the effective separation for the residual dyes in the aqueous solution is still an issue with great challenge in the area of environmental protection. Now, to high-efficiency removal of organic dyes from the aqueous solution, we design a unique AlOOH/CoFe2O4 adsorbent with porous CoFe2O4 nanoparticles embedded on the AlOOH fibers using a simple hydrothermal technique and calcination process. The structural properties and surface characteristics of the AlOOH/CoFe2O4 composites are detailedly analyzed by XRD, FTIR, XPS, TEM and SEM. Here, the high SBET and specific porous structure are beneficial to improve the adsorption performance of AlOOH/CoFe2O4 adsorbents. Especially, when the molar ratio of AlOOH to CoFe2O4 in the AlOOH/CoFe2O4 fibers is 1:1, an optimal performance on adsorbing anionic Congo red (CR) and cationic methyl green (MG) dyes can be obtained at pH = 6.29, where the corresponding maximum adsorption capacities reach up to 565.0 and 423.7 mg g−1, respectively. Factors leading to the change in the ability of adsorbing CR and MG dyes are systematically discussed, including contact time, temperature, initial concentrations, and pH values of the solutions. Meanwhile, the uptake of CR and MG dyes can best conform to Langmuir isotherm model and pseudo-second-order adsorption kinetics. The thermodynamic analysis verifies that the dye adsorption process is spontaneous and endothermic. Moreover, from the point view of practical application, the good reusability further makes the as-synthesized magnetic AlOOH/CoFe2O4 composite be a perfect adsorbent with efficiently removing both anionic and cationic dyes from aqueous solutions.

Bimetallic zeolitic imidazolate framework-derived nitrogen-doped porous carbon-coated CoFe2O4 core–shell composite with high catalytic performance for peroxymonosulfate activation in Rhodamine B degradation

The rational design and development of a highly efficient and sustainable heterogeneous catalyst has become a limiting factor for the practical application of persulfate-based advanced oxidation processes in organic dye degradation. Herein, a nitrogen-doped porous carbon-coated CoFe 2 O 4 core – shell composite (CoFe 2 O 4 @NPC) was synthesized by in-situ growth of cobalt/iron bimetallic zeolitic imidazolate framework-9 (Co/Fe-ZIF-9) on graphene oxide (GO) nanosheets followed by one-step calcination of the bimetallic ZIF-GO composite in nitrogen. The textural, chemical, and magnetic properties of the composites were comprehensively characterized using various analytical techniques. The catalytic performances of the as-prepared CoFe 2 O 4 @NPC in activating PMS to decompose Rhodamine B (RhB) were then systematically evaluated. The composite calcined at 600 °C exhibited the highest catalytic activity. The maximum RhB degradation efficiency of 99.05% and pseudo-second-order kinetic constant of 0.0766 L/(mg·min) were achieved after 20 min at 25 °C. Moreover, CoFe 2 O 4 @NPC displayed excellent recyclability and stability with negligible leaching of Co and Fe ions into the solution. Subsequently, electron spin resonance, reactive oxygen species quenching, and X-ray photoelectron spectroscopy were conducted to clarify the PMS activation mechanisms. Results suggested that SO 4 •− and •OH were generated during PMS activation and that SO 4 •− was the predominant radical involved in RhB degradation. In addition, Co(II), Fe(III), and structured nitrogen, especially pyridinic and graphitic N groups, participated in the PMS activation. Some insights into possible mechanisms of RhB degradation were also attained from spectral analyses. All these results suggested that CoFe 2 O 4 @NPC had excellent potential as a PMS activator for application in dye-contaminated wastewater treatment. • Nitrogen-doped porous carbon shell-coated CoFe 2 O 4 core – shell composites (CoFe 2 O 4 @NPC) prepared. • Multiple parameters influenced the catalytic performance of CoFe 2 O 4 @NPC. • CoFe 2 O 4 @NPC recyclable, stable, and resists the leaching of Co and Fe ions. • SO 4 •− is the principle radicals involved in the degradation of RhB. • Co(II), Fe(III) and structured nitrogen participated in the PMS activation process.

Adsorption Isotherms and Kinetics of the Adsorption of Rare Earth Elements {La(III)&Pr(III)} by Nanocobalt Ferrite

Background: Thermal decomposition of metal oxalates, which lead to transition metal oxide composite, is considered to be a versatile method for the synthesis of transition metal oxide composite and its extraordinary applications. Objectives: Nanometal oxide composite, especially, nanocobalt ferrite (CoFe2O4), is prepared efficiently in a simple, eco friendly and cost effective manner. Various characterization techniques like XRD, FTIR, SEM and EDS are applied to explore the morphology, functional groups, bonding nature and size of the nano particles synthesized. Adsorption of rare earth elements La(III) and Pr(III) onto synthesized nanocobalt ferrite is further studied using ICPAES method. Methods: Here, authors make an attempt to exploit meso porous CoFe2O4 synthesized through thermal decomposition method and exploited it as an adsorbent for the adsorption of REEs, namely Lanthanum and Praseodymium in their trivalent oxidation state La (III) & Pr (III) using ICPAES technique. Results and discussion: The influencing parameters such as the adsorption efficiency, which include equilibrium time, pH, initial rare earth element concentration, adsorbent dosage and effect of temperature are studied. Adsorption isotherms, kinetics and thermodynamic parameters are analyzed. Conclusion: It is observed that adsorption studies follow pseudo second order kinetics and follow adsorption isotherms of Langmuir. The adsorption capacity is observed to be more than 90%.

Porous cobalt ferrite microspheres decorated two-dimensional MoS2 as an efficient and wideband microwave absorber

In this article, the CoFe2O4/MoS2 composites have been well constructed via a facial hydrothermal method, from which the porous CoFe2O4 microspheres were embedded into MoS2 ultrathin nanosheets. As a typical two-dimensional transition metal sulfide, MoS2 with high electrical conductivity and flexible properties is expected to exhibit high dielectric loss and magnetic loss when combined with magnetic material CoFe2O4. Meanwhile, the unique hierarchical structure of as-synthesized MoS2 nanoflowers is conducive to scattering and reflection of electromagnetic waves, and endows designed composites with competitive microwave absorption properties. Notably, although the saturation magnetization of MoS2/CoFe2O4 composites is significantly decreased compared to pure CoFe2O4 microspheres, the coercivity still maintains a high value of 626.1 Oe. As expected, the results demonstrate that as-fabricated MoS2/CoFe2O4 composites do have superior microwave absorption properties in comparison with CoFe2O4 and MoS2. It is found that the complex permittivity is enhanced with increasing filling ratio from 45 wt% to 60 wt%, which is helpful for obtaining a moderate permittivity value. When the filling ratio is 50 wt%, the MoS2/CoFe2O4 composites exhibit a minimum reflection loss (RLmin) of − 53.1 dB at 12.08 GHz when the thickness is 2.5 mm. An effective absorption bandwidth less than − 10 dB of 6.61 GHz from 11.28 to 17.89 GHz is achieved with a thin thickness of 2.2 mm, almost covering the whole Ku-band. The improvement in microwave absorption properties can be ascribed to the synergistic effect of the magnetic CoFe2O4 and dielectric MoS2. The impedance matching characteristic and interfacial polarization are significantly optimized by inserting CoFe2O4 spheres onto the surface of MoS2 nanosheets. Considering the excellent performance of as-fabricated MoS2/CoFe2O4 composites, it is believed that the MoS2-based composites can be applied as a promising candidate of highly effective microwave absorbers with strong absorption intensity and broad absorption frequency.

Synthesis and characterization of TiO2 doped cobalt ferrite nanoparticles via microwave method: Investigation of photocatalytic performance of congo red degradation dye

Microwave improved porous CoFe2O4 and TiO2 doped CoFe2O4 nanostructures were designed using L-threonine as a fuel in our current research work. The synthesized nanomaterials were characterised and investigated to determine the photocatalytic degradation of congo red dye on irradiation of visible light. The powder XRD pattern proved that the obtained crystallite size of CoFe2O4 is 44 nm and TiO2 doped CoFe2O4 is 25 nm. It has been observed that the crystalline size is much lower for TiO2 doped CoFe2O4 when compared to the CoFe2O4, which is due to the doping of titania. Furthermore, the SEM images of titania doped CoFe2O4 indicates that the smaller particles are dispersed with a high agglomeration, due to the interfacial surface tension between the titania and cobalt ferrite particles. DRS spectra proved the measured bandgap of the corresponding CoFe2O4 and TiO2 doped CoFe2O4 nanostructures are 3.01 and 2.88 eV. The microstructure and the dimension of the synthesized CoFe2O4 and TiO2 doped CoFe2O4 spinel ferrites nanostructures were explored by high resolution transmission electron microscope (HR-TEM). The association of photocatalytic properties of CoFe2O4 and TiO2 doped CoFe2O4 in a solitary particle is the projected advantage of the current work.

Bimetal oxalate‐derived synthesis of laponite‐decorated CoFe2O4 porous nanostructures for activation of peroxymonopersulfate towards degradation of rhodamine B

AbstractBACKGROUNDAdvanced oxidation processes based on sulfate radical have been widely employed for oxidation degradation of organic contaminants. Catalytic activation of peroxymonopersulfate (PMS) with transition metal oxides holds great promise for the generation of sulfate radical. In this work, laponite‐decorated CoFe2O4 porous nanostructures have been prepared through the thermal decomposition of laponite/oxalates, and evaluated as a magnetic catalyst to activate PMS for the oxidation of rhodamine B (RhB).RESULTSThe decoration of porous CoFe2O4 microparticles with laponite was evidenced because of the presence of the vibration mode of SiO (at 1359 cm−1) in Fourier transform infrared spectra and the uniform distribution of Si and Mg elements from elemental mapping images. Decorating with laponite also resulted in an increase in amount of surface hydroxyl oxygen species, which facilitated the formation of CoOH complex for PMS activation. Furthermore, the enhanced activation of PMS with laponite‐decorated CoFe2O4 resulted in a faster removal (98.04%) of RhB as compared to undecorated CoFe2O4 (79.62%) within 56 min. Meanwhile, the rate constant increased from 0.0288 (CoFe2O4) to 0.0679 min−1 (laponite‐decorated CoFe2O4). The degradation rate of RhB progressively increased with reaction temperature and catalyst dosage. Scavenging and electron paramagnetic resonance tests manifested that the sulfate and superoxide radicals served as the major active species for the oxidation of RhB molecules.CONCLUSIONThe above results demonstrated positive effects of laponite on the textural property, surface chemical states and catalytic activity of porous CoFe2O4 microparticles. This study provides an insight into the promising role of laponite as an additive in improving PMS activation.

Novel method of preparing hierarchical porous CoFe2O4 by the citric acid-assisted sol-gel auto-combustion for supercapacitors

In this work, the hierarchical porous CoFe2O4 was fabricated by the citric acid-assisted sol-gel auto-combustion method. The hierarchical porous CoFe2O4 was applied as supercapacitor's electrode and exhibited good electrochemical properties. The specific capacitance of CoFe2O4 electrode can rich 443.89 F g−1 at current density of 1 A g−1, and 75.12% capacitance was still retained at current density of 16 A g−1 compared with 1 A g−1. The cycling stability was excellent, which degraded by 20.65% after 6000 cycles. The results suggest that the synthesized hierarchical porous CoFe2O4 was a promising candidate for application to supercapacitors electrodes. Meanwhile, the novel citric acid-assisted sol-gel auto-combustion is low manufacturing cost, simple in preparation, easy to control the stoichiometric ratio, which can be further extended to synthesize other inorganic materials.

Magnetic CoFe2O4 nanocrystals derived from MIL-101 (Fe/Co) for peroxymonosulfate activation toward degradation of chloramphenicol

In this study, porous magnetic CoFe2O4 nanocrystals (NCs) were successfully synthesized by using bimetal-organic framework (MOF) as a precursor, and used as catalysts to activate peroxymonosulfate (PMS) for the removal of chloramphenicol (CAP) in the solution. The structure and physicochemical properties of CoFe2O4 NCs were thoroughly examined by a series of characterization techniques. The results revealed as-synthesized CoFe2O4 had a nanorod-shaped structure with high specific surface area (83.00 m2 g−1) and pore volume (0.31 cm3 g−1). Furthermore, the degradation efficiency (100%) and the removal of total organic carbon (68.09%) were achieved after 120 min with 0.1 g/L CoFe2O4 NCs, 2 mM PMS and 10 mg/L CAP at pH of 8.20. In addition, effects of catalyst dosage, PMS dosage, initial pH values, CAP concentration and co-existing anions as well as natural organic matters in the solution on the degradation efficiencies were studied and all the removal can be well fitted with pseudo-first-order kinetic model (R2 > 0.96). Sulfate radicals (SO4•−) and hydroxyl radicals (HO•) were proved to be two main reactive species for CAP removal in CoFe2O4/PMS system based on quenching experiments. CAP was degraded by the main pathways of dichlorination, denitration, decarboxylation, hydroxylation, ring cleavage and chain cleavage on CoFe2O4/PMS system through high performance liquid chromatograph-mass spectrometry analysis. We believe that this study would be very meaningful to promote the applications of MOFs-derived catalysts on the SO4•− based advanced oxidation processes (SR-AOPs) for the environmental remediation.

Enhanced ammonia detection using wrinkled porous CoFe2O4 double-shelled spheres prepared by a thermally driven contraction process

Hierarchical CoFe2O4 double-shelled hollow spheres (DHSs) with wrinkled porous surfaces are successfully synthesized via a self-templating strategy followed by a simple post-annealing process. The crystallinity, morphology, and microstructure of CoFe2O4 DHSs are detailedly characterized. The as-prepared CoFe2O4 DHSs are composed of homogeneous primary nanoparticles with uniform size and morphology that are hierarchically assembled into well-defined double-shelled spheres with high porosity. The formation mechanism of double-shelled hollow structure is also discussed. Because of their large specific surface area and easily penetrable hierarchical shells, the as-synthesized CoFe2O4 DHSs exhibit high sensitivity to ammonia and fast response-recovery capability at the optimal working temperature.

Effects of binders on electrochemical sodium storage performance with porous CoFe2O4 nanocubes derived from metal-organic frameworks

Porous CoFe2O4 nanocubes (PCFO-NCs) was prepared simply by annealing metal-organic frameworks Prussian blue and used as anode with different binders for sodium ion batteries (SIBs). The water-soluble binders (carboxyl methyl cellulose, CMC and polyacrylic acid, PAA) significantly improve the cycling stability of PCFO-NCs, especially for the electrode with CMC binder. The electrodes with CMC and PAA binders show the capacities of 394 and 310 mAh g−1 after 50 cycles with good cycling stability. Electrochemical impedance spectroscopy shows that the CMC binder delivers the highest sodium diffusion coefficient, the lowest Rct and Ea, which facilitates the reactions at the electrode/electrolyte interface. These advantages highlight the potential applications of CMC binder in SIBs.

Synthesis of Porous CoFe2O4 and Its Application as a Peroxidase Mimetic for Colorimetric Detection of H2O2 and Organic Pollutant Degradation

Porous CoFe2O4 was prepared via a simple and controllable method to develop a low-cost, high-efficiency, and good-stability nanozyme. The morphology and microstructure of the obtained CoFe2O4 was investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), specific surface area and pore analysis, and Raman spectroscopy. The results show that the annealing temperature has an important effect on the crystallinity, grain size, and specific surface area of CoFe2O4. CoFe2O4 obtained at 300 °C (CF300) exhibits the largest surface area (up to 204.1 m2 g−1) and the smallest grain size. The peroxidase-like activity of CoFe2O4 was further verified based on the oxidation of peroxidase substrate 3,3’,5,5’-tetramethylbenzidine (TMB) in the presence of H2O2. The best peroxidase-like activity for CF300 should be ascribed to its largest surface area and smallest grain size. On this basis, an effective method of colorimetric detection H2O2 was established. In addition, the porous CoFe2O4 was also used for the catalytic oxidation of methylene blue (MB), indicating potential applications in pollutant removal and water treatment.

Porous CoFe2O4 nanocubes derived from metal-organic frameworks as high-performance anode for sodium ion batteries

Recently sodium ion batteries (SIBs) as a new energy storage system have attracted enormous interests. Unfortunately, the development of high-performance electrode materials for SIBs is restricted owing to the large volume change during sodium insertion and extraction. In this work, porous CoFe2O4 nanocubes (PCFO-NCs) were prepared simply by annealing metal-organic frameworks and used as anode materials for SIBs. The PCFO-NCs exhibit a high initial Coulombic efficiency of 68.8% and a maximum reversible capacity of 360mAhg−1 after 50 cycles at the current density of 50mAg−1, as well as good rate capability and excellent cycling stability at high current density. The excellent electrochemical performance can be attributed the short diffusion distance of sodium ion due to the good interfacial contact between electrode and electrolyte, and the buffering of volume change during charge/discharge processes by the porous structure.

Bimetal-Organic Framework Derived CoFe2 O4 /C Porous Hybrid Nanorod Arrays as High-Performance Electrocatalysts for Oxygen Evolution Reaction.

Porous CoFe2 O4 /C NRAs supported on nickel foam@NC (denoted as NF@NC-CoFe2 O4 /C NRAs) are directly fabricated by the carbonization of bimetal-organic framework NRAs grown on NF@poly-aniline(PANI), and they exhibit high electrocatalytic activity, low overpotential, and high stability for the oxygen evolution reaction in alkaline media.

Effect of starting solution acidity on the characteristics of CoFe2O4 powders prepared by solution combustion synthesis

Cobalt ferrite (CoFe2O4) nanoparticles were synthesized at the different pH values of starting solution, adjusted by NH4OH, using solution combustion method. Theoretical calculations and Fourier transform infrared spectroscopy analysis were carried out for determination and controlling the chelated species in solution. The phase evolution, surface area, morphology and magnetic properties of the combusted CoFe2O4 powders have been investigated by thermal analysis, X-ray diffractometry, electron microscopy, adsorption–desorption and vibrating sample magnetometer. The combustion rate mainly depends on pH which affects the phase and crystallite size. Furthermore, the specific surface area of the porous CoFe2O4 powders decreases from 66.25 to 27.09m2/g by the increase of pH from 2 to 10. The combusted CoFe2O4 powders exhibit ferromagnetic properties which the highest saturation magnetization of ~63.7emu/g was achieved at pH of 2. Furthermore, the coercivity increases from 1112 to 1225Oe by the increase of pH due to the decreasing of crystallite size.

Porous CoFe2O4 nanowire arrays on carbon cloth as binder-free anodes for flexible lithium-ion batteries

A three-dimensional CoFe2O4 nanowire array on carbon cloth was fabricated with a hydrothermal method together with a post-annealing treatment. As a binder-free and flexible anode material for LIBs, it showed an improved electrochemical performance with high cycling stability and excellent rate capability. It exhibited an initial discharge capacity of 1615mAhg−1 and retained a reversible capacity of about 1204mAhg−1 after 200 cycles at a specific current of 500mAg−1. The high capacity, outstanding rate performance and cycling stability can be attributed to the special configuration of hierarchal porous CoFe2O4 nanowires on carbon cloth, which possess many advantages like short diffusion length, easy strain relaxation and fast electron transport. Moreover, the integrated CoFe2O4 nanowires/carbon cloth electrode shows high flexibility and high areal capacity (2.41mAhcm−2), which makes it suitable for use as a binder-free anode to build flexible LIBs.

Effective removal of methylene blue from aqueous solution by MnO2-modified porous CoFe2O4 microrods

MnO2-modified porous CoFe2O4 microrods (MnO2–CMR) were prepared by in situ oxidation reaction. The obtained samples were characterized by the means of scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and energy dispersive spectrometer. The results showed that the CoFe2O4 microrods were successfully decorated with amorphous MnO2. An appropriate decoration mechanism was suggested and discussed. Methylene blue (MB) was employed to evaluate the adsorption property. The measurements exhibited that the adsorption capacity was highly enhanced due to the addition of MnO2 in the porous CoFe2O4 microrods (CMR). The adsorption capacity of the as-prepared MnO2–CMR was investigated using a batch adsorption procedure. The kinetics and thermodynamics of the adsorption process were further investigated. The adsorption kinetics was well fitted by a pseudo-second-order model and the adsorption isotherms agree well with the Langmuir model. Thermodynamic analyses showed that MB adsorption onto the MnO2–CMR was endothermic and spontaneous process. Furthermore, the MnO2–CMR can be easily recycled by magnetic separation. The MnO2–CMR developed in the present study was expected to be an efficient magnetic adsorbent for the removal of MB form wastewater.