Cobalt Nitrate Research Articles

Cobalt nanoparticle synthesis through the mechanochemical and chemical reduction method as a highly active and reusable catalyst for H2 production via sodium borohydride hydrolysis process

The process of hydrolysis of sodium borohydride is a new and clean method for the production of hydrogen. In this study, cobalt nanoparticles were synthesized by the mechanochemical and chemical reduction methods, and their catalytic performance was compared. The effect of using different cobalt precursors and reducing agents was investigated for the sample prepared via the chemical reduction method. The results showed that the cobalt catalysts synthesized through the chemical reduction method possessed better catalytic performance. Also, the sample prepared using cobalt nitrate and sodium borohydride had a higher hydrogen generation rate (HGR), which was equal to 3272.7 ml min−1g−1. The kinetics of the cobalt catalyst in the process have also been investigated, revealing that the rate of hydrogen production is dependent on the concentrations of sodium borohydride and sodium hydroxide, the catalyst dosage, and the process temperature. The crystal size of this catalyst was 21.6 nm with spherical agglomerated particles. The BET area of the best sample and its activation energy was equal to 11.18 m2g-1 and 22.3 kJmol-1, respectively. This catalyst was also stable in successive cycles.

Morphological features of Co3O4 nanoparticles obtained by solution combustion method

The global environmental crisis has made it imperative to enhance tools and techniques for monitoring and analyzing environmental parameters. Gas sensors, crucial for air quality assessment, continually under go technological advancements to enhance accuracy and efficiency in detecting harmful substances. They play an essential role in ensuring safety in workplaces, urban areas, and industries, aiding pollution control efforts. Enhanced gas sensor performance hinges on careful selection and control of gas-sensitive materials and their structure. This involves optimizing gas-sensitive compounds, employing advanced materials, and developing technologies for sensitive and rapid substance detection. One promising compound for this purpose is Co3O4 oxide, synthesized efficiently using the solution combustion method. This method off ers simplicity and allows for precise control over product structures and properties, enabling customization for specific requirements and ensuring high detection efficiency and accuracy. In this study, Co3O4 particles were synthesized from a mixture of cobalt nitrate and glycine with the addition of nitric acid using the solution combustion method. The influence of nitric acid addition and the fuel-to-oxidizer ratio on the morphological characteristics of the cobalt oxide was investigated. The results from SEM, TEM, XRD, and SAXS analyses confi rmed that the addition of nitric acid and a fuel-rich mixture lead to nanoparticles with smaller diameter spread and more stable characteristics.

Mechanism of carbon nanotube growth in expanded graphite via catalytic pyrolysis reaction using carbores P as a carbon source.

Carbon nanotubes (CNTs) had potential applications in energy conversion and storage devices, and it could be prepared by expanded graphite loaded with catalyst at high temperature, however, the mechanism of carbon nanotube growth in expanded graphite need further confirmation. In this work, carbon nanotubes' in situ growth in expanded graphite (EG) were prepared via catalytic pyrolysis reaction using carbores P as a carbon source and Co(NO3)3•6H2O as a catalyst. The results of X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscope (EDS) indicated the carbon nanotubes could generate in, EG with the presence of carbores P as a carbon source and cobalt nitrate as a catalyst. More interestingly, the growth mechanism of carbon nanotubes could be concluded by the results of differential thermal analysis-thermogravimetry-mass spectrometry (DTA-TG-MS) and X-ray photoelectron spectroscopy (XPS) analysis. The pyrolysis products of carbores P were mainly hydrocarbon gas such as CH4 gas, which reacts with Co(NO3)3·6H2O catalyst to reduces CoOx to Co particles, then the carbon form pyrolysis was deposited the on the surface catalyst Co particles and, after continuous solid dissolution and precipitation, carbon nanotubes were at last generated in EG at last.

Activation of peroxymonosulfate by a novel stratiform Co-MOF as catalyst for degradation of dyes in water

Cobalt-based metal-organic frameworks (MOFs) have been used as catalysts to remove macromolecular organic pollutants from wastewater. In this work, a novel type of cobalt-based MOF, CUST-593, was synthesized from cobalt nitrate hexahydrate (Co(NO3)2·6H2O), 2,2-bipyridine (BIPY), and 4,4ˊ,4ˊˊ-nitrilotrisbenzoic acid (NTB) using solvothermal method. The catalytic properties of CUST-593 for degrading dyes in water were then investigated. CUST-593, with the chemical formula {Co(NTB)(BIPY)(H2O)·0.5H2O·0.1DMA}, exhibited excellent catalytic activity in degrading dyes such as methyl orange (MO) and rhodamine B (RhB) in aqueous solutions. CUST-593 has a multi-layered structure, connected by carboxylate hydrogen bonds, which is beneficial to improving its water stability. Synthetic test results showed that CUST-593 effectively attacked dyes by primarily generating sulfate radicals (SO4•−) and a portion of hydroxyl radicals (•OH). Under the testing conditions, MO removal efficiency reached approximately 95 %. Moreover, CUST-593 exhibited remarkable cycling catalytic properties, broad pH range applicability, and long-term effectiveness. A mechanism for the degradation of dyes by CUST-593 was proposed. The experimental findings in this study collectively support the conclusion that CUST-593 serves as a green and environmentally friendly catalyst for the degradation of dyes in polluted water.

Synthesis and crystal structure of layered molybdate NH4Co2OH(MoO4)2⋅H2O

A new compound NH4Co2OH(MoO4)2⋅H2O was prepared by precipitation of aqueous solutions of cobalt nitrate and ammonium heptamolybdate at pH = 7.5. The crystal structure was identified by X-ray powder diffraction (XRPD) and Rietveld refinement as a known polymorph of layered molybdates (Φy) with general formula AT2OH(MoO4)2⋅H2O (A = NH4+, Na+, K+ and T = Zn2+, Co2+, Cu2+, Ni2+) and refined from a model based on that structure. The lattice parameters were refined with R-3 space group (148) a = 6.1014(2) Å, b = 6.1014(2) Å, c = 21.826(1) Å, α = 90°, β = 90°, and γ = 120°.

Facile Synthesis of Co Nanoparticles Embedded in N-Doped Carbon Nanotubes/Graphitic Nanosheets as Bifunctional Electrocatalysts for Electrocatalytic Water Splitting.

Developing robust and cost-effective electrocatalysts to boost hydrogen evolution reactions (HERs) and oxygen evolution reactions (OERs) is crucially important to electrocatalytic water splitting. Herein, bifunctional electrocatalysts, by coupling Co nanoparticles and N-doped carbon nanotubes/graphitic nanosheets (Co@NCNTs/NG), were successfully synthesized via facile high-temperature pyrolysis and evaluated for water splitting. The morphology and particle size of products were influenced by the precursor type of the cobalt source (cobalt oxide or cobalt nitrate). The pyrolysis product prepared using cobalt oxide as a cobalt source (Co@NCNTs/NG-1) exhibited the smaller particle size and higher specific surface area than that of the pyrolysis products prepared using cobalt nitrate as a cobalt source (Co@NCNTs/NG-2). Notably, Co@NCNTs/NG-1 displayed much lower potential -0.222 V vs. RHE for HER and 1.547 V vs. RHE for OER at the benchmark current density of 10 mA cm-2 than that of Co@NCNTs/NG-2, which indicates the higher bifunctional catalytic activities of Co@NCNTs/NG-1. The water-splitting device using Co@NCNTs/NG-1 as both an anode and cathode demonstrated a potential of 1.92 V to attain 10 mA cm-2 with outstanding stability for 100 h. This work provides a facile pyrolysis strategy to explore highly efficient and stable bifunctional electrocatalysts for water splitting.

Facile microwave assisted one-pot solid-state construction of Co-Fe spinel oxide/porous biochar for highly efficient 4-nitrophenol degradation: Effect of chemical blowing and surface vulcanization

Herein, microwave assisted one-pot solid-state construction method was developed for cellulose carbonization and Co-Fe spinel oxide loading to prepare Co-Fe spinel oxide/porous biochar for highly efficient 4-nitrophenol (4-NP) oxidation degradation through peroxymonosulfate (PMS) activation. With just 3 min domestic microwave heating of a solid mixture of cobalt nitrate, iron nitrate, α-cellulose, ammonium bicarbonate and thiourea, Co-Fe spinel and metal sulfides well dispersed, oxygen vacancies and pyrrole N enriched as well as BET increased porous Sx-CF@PC catalytic materials could be prepared with NH4HCO3 aided chemical blowing and thiourea assisted surface vulcanization. The optimal catalyst S1-CF@PC could achieve 99.0 % 4-NP removal in 10 min with rate constant as high as 0.564 min−1. Well dispersed spinel and metal sulfides could activate PMS to generate more SO4− and OH for 4-NP degradation; Meanwhile, oxygen vacancies and pyrrole nitrogen could promote 1O2 based non-free radical 4-NP degradation pathways. This study provided the simplest microwave assisted solid-state metal oxide/porous biochar construction for energetic organic pollutants degradation.

A CoFe2 Alloy‐Functionalized Few‐Layer Graphene Sheet Nanocomposite as an Electrocatalyst of the Oxygen Reduction Reaction

AbstractSearching for a high‐efficiency, recycled and cheap catalytic material for oxygen reduction reaction (ORR) is urgently needed in fuel cells. In this study, we successfully fabricated a nanocomposite consisting of CoFe2 alloy functionalized few‐layer graphene sheets (CoFe2/FLGs) by employing ferric nitrate, cobalt nitrate, and glucose as precursors. Various measurements conducted in this research confirm that the nanosized CoFe2 alloy particles are evenly dispersed within the FLGs and possess significant magnetism. Electrochemical measurements reveal that the CoFe2/FLGs exhibit a high positive onset potential (0.901 V), follow a four‐electron pathway, display a low Tafel slope (77.21 mV/dec), possess a low charge‐transfer resistance (∼72 Ω), and exhibit strong methanol tolerance. Consequently, the resulting CoFe2/FLGs nanocomposite demonstrates excellent electrocatalytic performance and recyclability for the ORR, positioning it as a promising catalyst for fuel cells.

Yeast-biotemplate-assisted fabrication of self-phosphorus doped Co3O4@C hollow architecture for ciprofloxacin degradation via peroxymonosulfate activation: Performance, mechanism and toxicity evaluation

Sustainable development of highly active catalysts for peroxomonosulfate (PMS) activation to destruct organic pollutants in wastewater has irreplaceable significance, but remains a challenge. Herein, we report the successful preparation of P-doped Co3O4 integrated porous carbon hollow architecture (Co3O4@PC-HM) using spherical yeast as a natural biological template and cobalt nitrate as a cobalt source. The unique hollow microspherical structure endows Co3O4@PC-HM with large specific surface area for providing copious surface-exposed active sites, and the self-P doping facilitates the electron transfer rate, which concomitantly contribute to boosting the PMS activation for ciprofloxacin (CIP) degradation. Specifically, the Co3O4@PC-HM exhibits an excellent performance for activating PMS to degrade CIP with a removal efficiency of 95% in 20 min. Quenching experiments and electron paramagnetic resonance tests indicate the coexistence of radical and non-radical pathways in the Co3O4@PC-HM/PMS system, among which 1O2 and SO4•− play the dominant roles in CIP degradation. Simultaneously, four possible pathways of CIP degradation with the Co3O4@PC-HM/PMS system are proposed. Toxicity evaluation based on ECOSAR procedure and the growth status of mung bean roots reveal that the degradation process catalyzed by the Co3O4@PC-HM/PMS system efficiently decreases the toxicity of CIP. The natural biological template strategy has guiding significance for the synthesis of other hollow structure for versatile applications.

Citrus fruit peel extract mediated eco-friendly synthesis of Ag @Co bimetallic nanoparticles and study of their optical and structural characterizations

The present study focuses on the preparation of Silver-Cobalt bimetallic nanoparticles by green method from metal precursors of silver nitrate & cobalt nitrate and the locally available lemon peel extract which is acts as a reducing and stabilizing agent. Firstly, the generation of bimetallic nano particles was observed by changing the colour in the reaction mixture. The optical measurements of the synthesized nano particles were studied by using UV–Visible spectroscopy. The results showed the maximum absorption wavelength at 447 nm for lemon peel extract. Further, the presence of functional groups in the prepared hybrid material was evaluated by FT-IR spectroscopy. Moreover, the crystallinity of as prepared nano particles was studied by using XRD analysis. The SEM results indicating that the produced bimetallic nano particles were predominately spherical in shape. In addition, the composition of elements of the developed hybrid material was examined by EDX analysis. Therefore, this newly developed method is simple, fast, cost-effective, eco-friendly and could prove alternative to physical and chemical routes for the preparation of nano particles.

(Digital Presentation) Prolonged Operation Strategies For Solid Oxide Fuel Cell Through Barrier Layer-Based Interface Engineering

As one of the current benchmark cathode materials, La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) is in the process of widely commercialization. Normally, a high-density barrier layer, such as doped Ceria (Gd0.1Ce0.9O2-δ, GDC), is essentially introduced in SOFC single cell between Zirconia electrolyte and cathode, in order to prevent chemical incompatibility and elements diffusion. However, in large-scale fabrication, the GDC barrier layer is typically screen-printed onto the as-sintered YSZ electrolyte. Consequently, the post-sintered GDC layer is often porous. Increase GDC barrier layer density can effectively facilitate oxygen ions transfer and inhibit elements diffusion. Therefore, in this study, four YSZ electrolyte supported symmetrical cathode cells with various barrier layers are investigated, i.e. (1) screen printed GDC (named as GDC), (2) screen printed GDC with Cobalt Nitrate sintering aid (GDC-Co), as well as hydrothermal modified cells named as (3) GDC-HY and (4) GDC-Co-HY, respectively. The results show largely decreased Rohm of ~20% when sintering aid are used in GDC barrier layer. Furthermore, both Rohm and Rp values are extremely stable after further hydrothermal modification, with growth rate of 0.014 and 0.03 Ω·cm2/kh for GDC-Co-HY, respectively, which are much lower than 0.22 and 0.248 Ω·cm2/kh for pristine GDC-Co. Current study suggests that increasing the GDC barrier layer density by hydrothermal modification is an effective method to enable better cell performance and more stable long-term operation.Figure 1 Evolution of (a) Rohm and (b) Rp with aging time in air. Microstructure of the GDC surfaces (c-f) and cell fractures (g-j). Figure 1

Effect of synthesis parameters on cobalt oxide nanostructures morphology

A facile approach was employed for the synthesis of cobalt oxide nanorods (NRs) using cobalt nitrate, sodium oxalate and ethylene glycol as precursors via a hydrothermal process. The hydrothermal conditions, such as temperature and time, were varied to optimize the morphological characteristics of the NRs. After undergoing filtration, washing, and drying, the resulting material was characterized using several techniques, including field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Our findings reveal that the NRs exhibit diverse morphologies, depending on the hydrothermal conditions, with the smallest aspect ratio observed when prepared at 200 °C for 24 hours. In addition, we investigated the gas sensing capabilities of the NRs to ammonia under these conditions.

A New Approach to the Preparation of Stable Oxide-Composite Cobalt–Samarium Catalysts for the Production of Hydrogen by Dry Reforming of Methane

A new approach to preparing a series of Co/Sm2O3 catalysts for hydrogen production by the dry reforming of methane has been developed. The catalyst precursors were synthesized with a simple method, including the evaporation of aqueous solutions of cobalt and samarium nitrates, followed by a short-term calcination of the resulting material. The as-prepared and spent catalysts were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, temperature-programmed reduction, and thermogravimetric analysis. The content of cobalt in the synthesized materials affects their phase composition and carbonization resistance in the dry reforming of the methane reaction. It has been shown that preheating in N2 atmosphere produces catalysts that provide a stable yield of hydrogen and CO of 94–98% for at least 50 h at 900 °C. These yields are among the highest currently available for the dry reforming of methane catalysts made from Co-Sm complex oxides. It has been established that the decrease in the amount of cobalt in the catalyst and its preheating to an operating temperature of 900 °C in a nitrogen flow help to prevent the carbonization of the catalyst and the sintering of metal particles.

Enhanced catalytic behavior of La2O2CO3/Co3O4 composite for thermal decomposition of ammonium perchlorate

In this work, La2O2CO3, Co3O4 and La2O2CO3/Co3O4 composites were prepared by one-step solution combustion with citric acid as oxidant and lanthanum nitrate and cobalt nitrate as reductants. Morphology analysis showed many pores of different sizes on the surface of the composite. The best catalytic performance was for the La2O2CO3/Co3O4 composite. The high-temperature decomposition (HDT) of ammonium perchlorate (AP) decreased by 187.7 °C, and the activation energy decreased from 371.6 to 140.6 kJ mol−1. The combustion process of AP/hydroxyl-terminated polybutadiene solid propellant containing La2O2CO3/Co3O4 was more intense, the ignition delay time was shortened from 30 to 25 ms and the time to reach maximum combustion effect was advanced from 370 to 190 ms. Through the mechanism analysis, we believe that the adsorption of NH3 by La2O2CO3 promotes AP decomposition and also causes breakage of N–H bonds, which accelerates the oxidative decomposition of NH3. The Co3O4 has unfilled 3d orbitals, which could accelerate electron transfer during the reaction. At the same time, the interface between the two substances leaks more active sites, further accelerating electron transfer. Therefore, La2O2CO3/Co3O4 composites are expected to be widely used in solid propellants.

A multi-scale study of 3D printed Co-Al2O3 catalyst monoliths versus spheres

This study demonstrates the characteristics of two model packing configurations: 3D printed (3DP) catalyst monoliths on the one hand, and their conventional counterparts, packed beds of spheres, on the other. Cobalt deposited on alumina is selected as a convenient model system for this work, due to its wide spread use in many catalytic reactions. 3DP constructs were produced from alumina powder impregnated with cobalt nitrate while the alumina spheres were directly impregnated with the same cobalt nitrate precursor. The form of the catalyst, the impregnation process, as well as the thermal history, were found to have a significant effect on the resulting cobalt phases. Probing the catalyst bodies in situ by XRD-CT indicated that the level of dispersion of identified Co phases (Co3O4 reduced to CoO) across the support is maintained under reduction conditions. The packed bed of spheres exhibits a non-uniform distribution of cobalt phases, including a core-shell morphology with an average crystallite size of 10–14 nm across the sphere, while the 3DP monolith exhibits a uniform distribution of cobalt phases with an average crystallite size of 5–12 nm upon reduction from Co3O4 to CoO. Computational Fluid Dynamics (CFD) modelling was carried out to develop digital twins and assess the effect of the geometry of both configurations on the pressure drop and velocity profiles. Finally, the activity of both Cobalt-based catalyst geometries was assessed in terms of their conversion, selectivity and turn over frequencies under model multiphase (selective oxidation) reaction conditions, which showed that the desired 3D printed monolithic geometries can offer distinct advantages to the reactor design.

Unusual bi- and tetra-nuclear cobalt(II) bis(salamo)-based complex: Preparation, crystal structure and theoretical calculations and fluorescence properties

Two unusual bis(salamo)-based Co(II) complexes, [Co2(L)(OMe)]·2MeOH (1) and [Co4(L1)4(MeOH)4] (2) were designed and successfully prepared, and characterized structurally. The crystal structure analysis showed that complex 1 is composed of one fully deprotonated ligand (L)3− moity, two divalent Co(II) atoms and one bridge-coordinated methanol molecule, while complex 2 is an asymmetric homotetranuclear structure made up of four Co(II) atoms, four fully deprotonated (L1)2− units and four coordinated methanol molecules. It is noteworthy that the reaction of cobalt(II) nitrate with H3L produces complex 2. This complex is not obtained from the original ligand H3L but from a new ligand H2L1. Therefore, the phenomenon can be used to prepare metal(II/III) complexes with excellent structure. The molecular frontier orbitals HOMO and LUMO of H3L and complexes 1 and 2 were analyzed by DFT calculations, and the results showed that the energy gaps of the complexes were reduced due to the combination of the orbitals compared to the ligand. The reaction sites of H3L with Co(II) atoms were analyzed by ESP studies, and the results showed that the crystal structures of the complexes are consistent with the theoretical predictions. Hirshfeld surface analyses indicated the different interactions in the complexes, and revealed that the main contributions to the crystal stacking were from HH, CH and HO interactions. The interactions in the complexes were further explored by IRI research, the results exhibited that there are abundant interactions in complexes 1 and 2, which are important for their construction of supramolecules. The fluorescence strengths of complexes 1 and 2 are significantly lower compared to H3L, which can be attributed to the ligand to metal charge transition (LMCT).

Synthesis of cobalt molybdenum nitrides by a gas-solid reaction – In situ XRPD study

The solid-gas reaction of the physical mixtures of cobalt(II) nitrate hexahydrate and ammonium molybdate tetrahydrate with gaseous ammonia was studied. The process was examined with the use of in situ X-ray powder diffraction (XRPD). Mixtures of cobalt molybdenum nitrides Co2Mo3N and Co3Mo3N were obtained at 700 °C. CoMoO4, Co2Mo3O8, Mo2N and metallic cobalt were identified as intermediates. The presented synthesis method allows the direct route of cobalt molybdenum nitrides formation without the wet preparation of oxidic precursor.

Theoretical and experimental investigation on rapid and efficient adsorption characteristics of microplastics by magnetic sponge carbon

Microplastic pollution control has always been a thorny problem all over the world. Magnetic porous carbon materials have shown a good development prospect in microplastic adsorption due to their excellent adsorption performance and easy magnetic separation from water. However, the adsorption capacity and rate of magnetic porous carbon on microplastics are still not high, and the adsorption mechanism is not fully revealed, which hinders its further development. In this study, magnetic sponge carbon was prepared using glucosamine hydrochloride as the carbon source, melamine as the foaming agent, iron nitrate and cobalt nitrate as the magnetizing agents. Among them, Fe-doped magnetic sponge carbon (FeMSC) exhibited excellent adsorption performance for microplastics due to its sponge-like morphology (fluffy), strong magnetic properties (42 emu/g) and high Fe-loading (8.37 Atomic%). FeMSC could adsorb to saturation within 10 min, and the adsorption capacity of polystyrene (PS) reached as high as 369.07 mg/g in 200 mg/L microplastic solution, which was almost the fastest adsorption rate and highest adsorption capacity reported so far in the same condition. The performance of the material against external interference was also tested. FeMSC performed well in a wide pH range and different water quality, except in the strong alkaline condition. This is because the surface of microplastics and adsorbents will have many negative charges under strong alkalinity, significantly weakening the adsorption. Furthermore, theoretical calculations were innovatively used to reveal the adsorption mechanism at the molecular level. It was found that Fe-doping could form chemisorption between PS and the adsorbent, thereby significantly increasing the adsorption energy between the adsorbent and PS. The magnetic sponge carbon prepared in this study has excellent adsorption performance for microplastics and can be easily separated from water, which is a promising microplastic adsorbent.

The effect of ammonium citrate on CoP/CC morphology and its electrocatalytic hydrogen evolution performance

The development and improvement of new transition metal-based catalysts to replace Pt/C electrodes in electrolytic water hydrogen evolution has attracted much attention.In this work, we used ammonium citrate as additive, mixed with cobalt nitrate, through hydrothermal and phosphating methods to get supported on carbon cloth catalyst with new morphology (referred to as E380-CoP/CC, E380 stands for ammonium citrate). Benefit from the dense and fine nanosheet structure,compared with cobalt phosphating alone, the catalyst E380-CoP/CC has a significant improvement in hydrogen evolution performance. In 1 M KOH, the overpotential is 57 mV at the current density of 10 mA cm−2, and the Tafel slope is only 40 mV dec-1, which is very close to the hydrogen evolution performance of Pt/C electrode. In addition, the catalyst has favorable stability and superior hydrogen evolution performance after undergoing CV 2000 cycles and 48 h i-t test. This work offers a reliable idea for realizing electrolytic water hydrogen evolution technology with high efficiency and energy saving.

MAGNETIC AND MICROWAVE ABSORBING PROPERTIES IN SEMI-HARD COXFE(3-X)O4 SYNTHESIZED BY SOL-GEL METHOD

Magnetic and microwave absorption properties of CoxFe(3-x)O4 semi-hard materials (x = 0.75, 1.0, and 1.5) synthesized have been carried out using the chemical method of sol-gel. The mixture of iron nitrate Fe2(NO3)3 and cobalt nitrate Co(NO3)2 dissolved in ethylene glycol, then the mixture was heated while stirring at 60 °C for 1 hour to form a gel. After that dried at a temperature of 120°C for 5 hours. A fine powder of CoxFe(3-x)O4 was obtained through the grinding process. The CoxFe(3-x)O4 powder crystallization was done by sintering at 1000 °C for 5 hours. The X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Vibrating-sample magnetometer (VSM), and Vector Network Analyzer (VNA) is used to investigate phase identification, particle morphology, magnetic properties, and microwave absorption ability, respectively. Based on the phase identification show that the samples with composition x = 0.75 have two phases, namely CoFe2O4 and Fe2O3. The sample composition for x ³ 1 is a single phase of CoFe2O4. The particle morphology is homogeneous with spherical and the particle size is about 100 – 500 nm. The samples act ferromagnetic behavior with a saturation magnetization (Ms) of 26.1-40.4 emu/g and coercivity field (Hc) of 223-299 Oe. The maximum reflection loss (RL) value of -14.03 dB at the frequency 10.98 GHz occurred in a single-phase sample with a composition of x = 1.0. This study provided a new composite material with great potential for the development of microwave-absorbing materials.