Cobalt Oxide Nanoparticles Research Articles

Development of manganese cobalt oxide (MnCo2O4) nanoparticle as multifunctional agents for antibacterial, anticancer and dye degradation applications

This study addresses the pressing concern of dye effluent contamination in water bodies and proposes a multifaceted solution through the synthesis and application of Manganese cobalt oxide (MnCo2O4) nanoparticles. The nanoparticles were prepared hydrothermally using acetate precursors, and their composition was carefully confirmed by XRD, FTIR, UV-DRS, FESEM, and EDX studies. The prepared MnCo2O4 nanoparticles, when exposed to the best-suited conditions (20 mL of dye solution containing 2.5 mg of MnCo2O4 NP kept at direct sunlight for 24 h, reaction time), exhibited remarkable efficiency in completely breaking down inorganic dyes, with removal percentages of 78.8 % for Methyl blue (MB) and 97.6 % for Congo red (CR). Notably, the synthesized MnCo2O4 nanoparticles display strong antibacterial capabilities against multidrug-resistant bacteria and considerable anticancer effects on the cervical cancer cell line (HeLa), as verified by the MTT assay. This comprehensive investigation positions the MnCo2O4 nanoparticle as a promising candidate for efficient wastewater treatment, a robust antibacterial agent, and a potential therapeutic agent against cervical cancer, highlighting its diverse and impactful applications.

Strain-driven magnetic transition of intercalated pressure-stabilized cobalt and cobalt oxide nanoparticles in linked graphene oxide nanoscale reactors

The study of the evolution and metamorphosis of nanoparticles under high pressure and in nanoscale confinement is a rapidly developing field that promises a diverse range of fundamental research and application opportunities. Here, we demonstrate how a linked and strained graphene oxide (GO)-based confinement system, functioning as a nanoscale reactor at high pressures, allows the evolution of the magnetic properties of an in situ generated composite cobalt (Co) nanoparticle system and further enables the retention of such properties when the pressure of the system is returned to ambient. We posit that this phenomenon is due to an ‘induced pressure’ created by strain, on the flexible planes of the 2D GO system, created by the intercalated Co-based nanoparticles. For graphene/GO this strain is characterized by shifts in the Raman “G-band”. Specifically, the studied system comprises in situ generated Co-containing nanoparticles confined between linked GO layers upon pressurization between 0 and 25 GPa. After quenching to ambient pressure, each of these samples exhibited innate ferromagnetic behaviors, demonstrating that our confinement system can be used to ‘lock in’ phase changes created by the application of transient high pressure. Importantly, while the unpressurized sample exhibited antiferromagnetic Co3O4 nanoparticles of ∼4 nm size, the samples pressurized to 10 GPa and 25 GPa, presented ferromagnetic order on the shell of an antiferromagnetic core of Co3O4 and CoO.

Cobalt Oxide Nanoparticle Synthesis by Cell-Surface-Engineered Recombinant Escherichia coli and Potential Application for Anticancer Treatment.

Cell surface display engineering facilitated the development of a cobalt-binding hybrid Escherichia coli. OmpC served as the molecular anchor for showcasing the cobalt-binding peptides (CBPs), creating the structural model of the hybrid OmpC-CBPs (OmpC-CP, OmpC-CF). Subsequently, the recombinant peptide's cobalt adsorption and retrieval effectiveness were evaluated at various concentrations. When subjected to a pH of 7 and a concentration of 2 mM, OmpC-CF exhibited a significantly higher cobalt recovery rate (2183.87 mol/g DCW) than OmpC-CP. The strain with bioadsorbed cobalt underwent thermal treatment at varying temperatures (400 °C, 500 °C, 600 °C, and 700 °C) and morphological characterization of the thermally decomposed cobalt nanoparticle oxides using diverse spectroscopy techniques. The analysis showed that nanoparticles confined themselves to metal ions, and EDS mapping detected the presence of cobalt on the cell surface. Finally, the nanoparticles' anticancer potential was assessed by subjecting them to heating at 500 °C in a furnace; they demonstrated noteworthy cytotoxicity, as evidenced by IC50 values of 59 μg/mL. These findings suggest that these nanoparticles hold promise as potential anticancer agents. Overall, this study successfully engineered a recombinant E. coli capable of efficiently binding to cobalt, producing nanoparticles with anticancer properties. The results of this investigation could have significant implications for advancing novel cancer therapies.

Modulating CO hydrogenation activity through silane functionalization of cobalt catalysts

Cobalt oxide (CoO) nanoparticles (NPs) were modified with different silanes (tetraethoxysilane – TEOS, triphenyl ethoxysilane – TPES, or trimethyl chlorosilane - TMCS) by dispersing the as-synthesized CoO NPs in n-hexane solutions containing the silanes. Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of these silanes on the cobalt surfaces even after reduction in hydrogen (H2) at 573 K. Modifying CoO-NPs with TEOS resulted in face-centred cubic (fcc)-cobalt phase upon reduction whereas TPES or TMCS modification induced a mixture of hexagonal close-packed (hcp)- and fcc-cobalt phases. The modification of cobalt surfaces with the silanes alters the adsorption properties of carbon monoxide (CO) on the catalytically active sites. Furthermore, temperature programmed desorption of CO (CO-TPD) showed that the amount of dissociatively adsorbed CO relative to amount of associatively adsorbed CO increases on silane-modified cobalt surfaces, which correlates with an improved rate of CO conversion in the Fischer-Tropsch CO hydrogenation.

Encapsulation hierarchical bimetallic oxide with flexible electrospinning carbon nanofibers for efficient capacitive deionization

Water scarcity, an intensifying issue, has spurred extensive research into the development of sophisticated freestanding pseudocapacitive electrode materials. Characterized by their precise morphology, intricate mechanics, and superior desalination capabilities, these materials are revolutionizing water treatment technologies. However, their broad adoption is hampered by complex fabrication processes and the necessity for various unique components. Herein, the paper introduces a streamlined method combining electrospinning and carbonization to produce a freestanding nitrogen-doped carbon nanofiber encapsulating manganese cobalt oxide (MCO) nanoparticles for desalination purposes. The approach significantly enhances interfacial interactions, mitigates volume shifts during sodium ion adsorption and desorption, and strengthens interfacial stability. Benefiting from its structural and compositional merits, the optimal MCO-1.0 electrode showcases exceptional electrochemical attributes. It achieves an impressive desalination efficiency (34.68 mg g−1), swift capacitive deionization rate (0.58 mg g−1 min−1), and superior cyclic durability. The study enhances our understanding of freestanding carbon fibers encapsulated with metal oxide nanoparticles, a key step toward developing robust electrodes for industrial applications.

Temperature-induced variations in the structural, morphological and optical features of cobalt oxide nanoparticles synthesized via hydrothermal method

Cobalt oxide is a promising material that attracts the researchers to find its application in various fields like catalysts, dielectric applications, gas sensors and electronics devices, etc. In this work, we investigated the effect of temperature in the structural, elemental, morphological and optical properties of Co3O4 nanoparticles synthesized by hydrothermal method. The as-prepared and annealed samples were observed for their structural and optical properties. The structural analysis and micro-strain effects of Co3O4 nanoparticles with cubic spinel structure were carried out through X-ray diffraction (XRD) studies. The crystallite size of as-prepared and annealed samples were around 27 nm and 29 nm, respectively. Raman spectrum showed the lattice vibrations of both oxidation states of cobalt oxide nanoparticles. Elemental analysis were observed through X-ray photoelectron spectroscopy (XPS). The morphology and chemical composition of the samples were determined from the field emission scanning electron microscope (FESEM) image and energy dispersive X-ray spectroscopy (EDAX). Moreover, the internal structure of both samples were compared through transmission electron microscopic (TEM) studies. The optical studies were done using the absorption spectrum and photoluminescence spectroscopy. Two direct band gaps (1.8 and 3.2 eV) were observed in the as-prepared, which got red-shifted on annealing (1.7 and 2.5 eV) due to size effects. The charge transfer process in two oxidation states of cobalt oxide could be identified from these bandgaps. Emission peaks in the photoluminescence spectrum of samples are due to the recombination of free-excitons and point defects in the crystal lattice.

Biologically inspired nanoformulations for the control of bacterial canker pathogens Clavibacter michiganensis subsp. michiganensis and subsp. capsici

Clavibacter michiganensis subsp. michiganensis (Cmm) and C. michiganensis subsp. capsici (Cmc) are phytopathogenic bacteria that cause bacterial canker disease in tomatoes and peppers, respectively. Bacterial canker disease poses serious challenges to solanaceous crops, causing significant yield losses and economic costs. Effective management necessitates the development of sustainable control strategies employing nanobiotechnology. In this study, the antibacterial effects of four Aspergillus sojae-mediated nanoformulations, including cobalt oxide nanoparticles (Co3O4 NPs), zinc oxide nanoparticles (ZnO NPs), cobalt ferrite nanoparticles (CoFe2O4 NPs), and CoFe2O4/functionalized multi-walled carbon nanotube (fMWCNT) bionanocomposite, were evaluated against Cmm and Cmc. The diameters of the zone of inhibition of A. sojae-mediated Co3O4 NPs, ZnO NPs, CoFe2O4 NPs, and CoFe2O4/fMWCNT bionanocomposite against Cmm and Cmc were 23.60 mm, 22.09 mm, 27.65 mm, 22.51 mm, and 19.33 mm, 17.66 mm, 21.64 mm, 18.77 mm, respectively. The broth microdilution assay was conducted to determine the minimal inhibitory and bactericidal concentrations. The MICs of Co3O4 NPs, ZnO NPs, CoFe2O4 NPs, and CoFe2O4/fMWCNT bionanocomposite against Cmm were 2.50 mg/mL, 1.25 mg/mL, 2.50 mg/mL, and 2.50 mg/mL, respectively. While, their respective MBCs against Cmm were 5.00 mg/mL, 2.50 mg/mL, 5.00 mg/mL, and 5.00 mg/mL. The respective MICs of Co3O4 NPs, ZnO NPs, CoFe2O4 NPs, and CoFe2O4/fMWCNT bionanocomposite against Cmc were 2.50 mg/mL, 1.25 mg/mL, 5.00 mg/mL, and 5.00 mg/mL. While, their respective MBCs against Cmc were 5.00 mg/mL, 2.50 mg/mL, 10.00 mg/mL, and 10.00 mg/mL. The morphological and ultrastructural changes of Cmm and Cmc cells were observed using field-emission scanning and transmission electron microscopy before and after treatment with sub-minimal inhibitory concentrations of the nanoformulations. Nanoformulation-treated bacterial cells became deformed and disrupted, displaying pits, deep cavities, and groove-like structures. The cell membrane detached from the bacterial cell wall, electron-dense particles accumulated in the cytoplasm, cellular components disintegrated, and the cells were lysed. Direct physical interactions between the prepared nanoformulations with Cmm and Cmc cells might be the major mechanism for their antibacterial potency. Further research is required for the in vivo application of the mycosynthesized nanoformulations as countermeasures to combat bacterial phytopathogens.

Studies on structural and optical properties of cobalt oxide nanoparticles using co-precipitation

This article aimed to study the structural and optical properties of cobalt oxide (Co3O4) nanoparticles made using the co-precipitation method. The structural, morphological, and optical properties of as synthesized product were studied using an X-ray diffractometer (XRD), scanning electron microscopy (SEM), and UV–vis absorption spectroscopy, respectively. The XRD pattern of the sample with the refinement revealed the synthesized Co3O4 sample had a cubic structure with an average of 11.5 nm-sized crystallites. The SEM of the sample resulted in an agglomerated spherical shape. EDX confirmed the presence of cobalt (Co) and oxygen (O) elements in the sample. The Williamson-Hall method yields anisotropic Co3O4NPs with an average crystal size consistent with the XRD findings.Theoptical property has signified that the (direct, indirect) band gap of Co3O4NPs is between(1.60, 1.58) eV and (2.40, 2.13) eV, indicating (O2−→Co3+) and (O2−→Co2+) charge transferprocesses. Due to their optical properties, Co3O4nanoparticles may be used for photocatalysis, solar cells, supercapacitors, batteries, and sensing applications.

Processing polymer film nanocomposites of poly(vinylidene fluoride)/poly(ethylene oxide) and cobalt oxide nanoparticles for flexible energy storage systems

Processing polymer film nanocomposites of poly(vinylidene fluoride)/poly(ethylene oxide) and cobalt oxide nanoparticles for flexible energy storage systems

Biocompatible Cobalt Oxide Nanoparticles for X-ray Fluorescence Microscopy.

The synthesis of water-soluble nanoparticles is a well-developed field for ferrite-based nanoparticles with the majority consisting of iron oxide or mixed metal iron oxide nanoparticles. However, the synthesis of non-agglomerated non-ferrite metal/metal oxide NPs is not as well established. The synthesis and characterization of uniform 20 nm, biologically compatible cobalt oxide (CoO) nanoparticles (NPs) is described. These nanoparticles have two principle components: 1) a CoO core of suitable size to contain enough cobalt atoms to be visualized by X-ray fluorescence microscopy (XFM) and 2) a robust coating that inhibits NP aggregation as well as renders them water-soluble and biocompatible (i.e. stealth coatings). Stable cobalt oxide NPs are obtained with octadecyl amine coatings as reported by Bhattacharjee. Two strategies for solubilizing these NPs in water were investigated with varying degrees of success. Exchanging the octadecyl amine coating for a nitrodopamine anchored PEG coating yielded the desired water-soluble NPs but in very low yield. Alternately, leaving the octadecyl amine coating on the NP and interdigitating this with a maleic anhydride-vinyl copolymer with different hydrophobic sidechains followed by opening the maleic anhydride ring with amine substituted PEG polymers (the water solubilizing component), yielded the desired water soluble NPS were obtained in good yield. Characterization data for the nanoparticles and the components of the coatings required for bioorthogonal reactions to ligate them with biotargeting agents are also described.

Selective Recognition of Lead and Cadmium in Potable Water Using Single Polypyrrole Nanowire Decorated with Cobalt Oxide Nanoparticles Electrode

The fabrication and characterization of a high-performance, robust, and highly sensitive sensor based on a single polypyrrole nanowire (sPpy NW) decorated with cobalt oxide nanoparticles (CoOxNPs) for the selective recognition of lead (Pb2+) and cadmium (Cd2+) in potable water are described in this paper. The electrodeposition technique was used to prepare the sPpyNW/CoOxNPs assembly, and square wave anodic stripping voltammetry (SW-ASV) was used to assess sensor performance. Optimizing sensor performance, such as deposition time, deposition potential, and supporting electrolyte, was used to assess for best sensor performance. The developed sensor exhibited excellent linearity and the linear range for the detection of individual Cd2+ and Pb2+ ions was determined to be 0.00 to 0.11 μM and 0.00 to 0.12 μM, respectively. The detection limits observed for both Pb2+ and Cd2+ sensors are 0.22 μM (R2 = 0.9520) and 0.013 μM (R2 = 0.9723), respectively. The linear range for the detection of Pb2+ and Cd2+ sensors present in the same sample was determined to be 0.00 to 0.09 μM, with a detection limit of 0.026 μM (R2 = 0.8726) and 0.013 μM (R2 = 0.9468) for Pb2+ and Cd2+, respectively. The observed results revealed that the functionalization of CoOxNPs on the surface of a sPpyNW electrode seems to be a very effective way of developing a sensitive, selective, and stable electrochemical sensor for Pb2+ and Cd2+ions.

Photocatalytic, antibacterial and antioxidant potential of spheroidal shape chromium and yttrium doped cobalt oxide nanoparticles: A green approach

This study delves into the versatile attributes of green synthesis of chromium doped cobalt oxide and yttrium doped cobalt oxide nanoparticles, synthesized through a sustainable process utilizing phytochemicals extracted from Bergera koenigii. The primary focus is on evaluating their effectiveness in photocatalysis, antibacterial activity, and antioxidant properties. The cubic structure of both chromium doped cobalt oxide and yttrium doped cobalt oxide nanoparticles was confirmed through X-ray diffraction analysis with crystallite size of 14.204 and 12.949 nm, respectively. Transmission electron microscopy and Scanning electron microscopy and Energy Dispersive X-ray spectroscopy examinations revealed the presence of spheroidal nanoparticles ranging from 37 to 41 nm in size. Photocatalytic efficiency, assessed through congo red dye degradation, demonstrated degradation of 86.963 and 94.499 % for chromium doped cobalt oxide and yttrium doped cobalt oxide nanoparticles, respectively. Antibacterial evaluations underscored the nanoparticles capacity to disrupt Bacillus subtilis and Escherichia coli, with yttrium doped cobalt oxide nanoparticles exhibiting superior antibacterial activity compared to chromium doped cobalt oxide nanoparticles. The antioxidant potential, evaluated via the 2,2-diphenyl-1-picrylhydrazyl free radical assay, showcased the nanoparticle's ability to scavenge free radicals, with yttrium doped cobalt oxide nanoparticles displaying highest scavenging up to 83.359 % which attributed to the introduced phytochemicals during the green synthesis process. The innovation of this research lies in the green synthesis of chromium doped cobalt oxide and yttrium doped cobalt oxide nanoparticles, harnessing their distinct properties for synergistic applications. The study provides valuable insights into potential future applications, offering novel solutions for environmental remediation and biomedical uses.

Metal-Organic Framework PCN-224 Combined Cobalt Oxide Nanoparticles for Hypoxia Relief and Synergistic Photodynamic/Chemodynamic Therapy.

Photodynamic therapy (PDT) and chemodynamic therapy (CDT) are promising tumor treatments mediated by reactive oxygen species (ROS), which have the advantages of being minimally invasive. However, the hypoxia of tumor microenvironment and poor target ability often reduce the therapeutic effect. Here we propose a tumor targeted nanoplatform PCN-224@Co3O4-HA for enhanced PDT and synergistic CDT, constructed by hyaluronate-modified Co3O4 nanoparticles decorated metal-organic framework PCN-224. Co3O4 can catalyze the decomposition of highly expressed H2O2 in tumor cells to produce oxygen and alleviate the problem of hypoxia. It can also produce hydroxyl radicals according to the Fenton-like reaction for chemical dynamic therapy, significantly improving the therapeutic effect. The cell survival experiment showed that after in vitro treatment, 4T1 and MCF-7 cancer cells died in a large area under the anaerobic state, while the survival ability of normal cell L02 was nearly unchanged. This result effectively indicated that PCN-224@Co3O4-HA could effectively relieve tumor hypoxia and improve the effect of PDT and synergistic CDT. Cell uptake experiments showed that PCN-224@Co3O4-HA had good targeting properties and could effectively aggregate in tumor cells. In vivo experiments on mice, PCN-224@Co3O4-HA presented reliable biosafety performance, and can cooperate with PDT and CDT therapy to prevent the growth of tumor.

An electrochemical sensing potential of cobalt oxide nanoparticles towards citric acid integrated with computational approach in food and biological media

Although citric acid (CA) has antioxidant, antibacterial, and acidulating properties, chronic ingestion of CA can cause urolithiasis, hypocalcemia, and duodenal cancer, emphasizing the need for early detection. There are very few documented electrochemical-based sensing methods for CA detection due to the challenging behavior of electrode fouling caused by reactive oxidation products. In this study, a novel, non-enzymatic, and economical electrochemical sensor based on cobalt oxide nanoparticles (CoOxNPs) is successfully reported for detection CA. The CoOxNPs were synthesized through a simple thermal decomposition method and characterized by SEM, FT-IR, EDX, and XRD techniques. The proposed sensing platform was optimized by various parameters, including pH (7.0), time (15 min), and concentration of nanoparticles (100 mM) etc. In a linear range of 0.05–2500 μM, a low detection limit (LOD) of 0.13 μM was achieved. Theoretical calculations (ΔRT), confirmed hydrogen bonding and electrostatic interactions between CoOxNPs and CA. The detection method exhibited high selectivity in real media like food and biological samples, with good recovery values when compared favorably to the HPLC method. To facilitate effective on-site investigation, such a sensing platform can be assembled into a portable device.

Green Fabrication of Cobalt Oxide Nanoparticles by Bacillus megaterium and Their Antibacterial Activities

Green Fabrication of Cobalt Oxide Nanoparticles by Bacillus megaterium and Their Antibacterial Activities

General and Facile Synthesis of Co/CoO Nanoparticals Supported by Nitrogen-Doped Graphenic Networks as Efficient Oxygen Electrocatalyst for Zn-Air Batteries.

Reasonable design of low-cost, high-efficiency and stable bifunctional oxygen electrocatalysts is of great significance to improve the reaction efficiency of Zn-air batteries, which is still a huge challenge. Here, we report a highly efficient bifunctional oxygen electrocatalyst with three-dimensional (3D) N-doped graphene network-supported cobalt and cobalt oxide nanoparticles (Co/CoO-NG), which can be in situ synthesized by inducing metal ions on metal plates via graphene oxide as an inducer. This 3D network structure and open active center show excellent bifunctional oxygen electrocatalytic activity under alkaline conditions, and can be used as an air electrode in rechargeable Zn-air batteries, with significantly better power density (244.28 mW cm-2) and stability (over 340 h) than commercial Pt/C+RuO2 mixtures. This work is conducive to advancing the practical application of graphene-based materials as air electrodes for rechargeable zinc-air batteries.

Metal-organic framework cobalt gallate derived high-voltage carbon coated lithium cobalt oxide cathode and porous carbon supported cobalt oxide anode materials for superior lithium-ion storage

Exploring innovative green synthesis strategies for both cathode and anode materials with improved lithium-ion storage capabilities is of great importance in developing advanced lithium-ion batteries. In this work, a metal-organic framework (MOF) typed sample cobalt gallate (Co-GA), prepared by the direct redox coprecipitation reaction using gallic acid (GA) molecules and metallic cobalt (Co) foils in mild hydrothermal condition, is employed as a precursor for engineering electrode materials for lithium-ion batteries with high atomic efficiency and low environmental impact. Taking the advantages of the unique microstructure and chemical composition of MOF materials, the Co-GA precursor can be easily converted to a rod-like porous carbon framework confined cobalt oxide nanoparticle anode material (Co3O4/RPC) and a thin carbon layer coated nanosized lithium cobalt oxide (LiCoO2) cathode material (LCO/C), respectively, by simply changing the solid-state reaction conditions. In half-cells with metallic lithium as counter electrode, the LCO/C cathode delivers a stable reversible capacity of 189.33 mAh·g−1 after 100 cycles at 200 mA·g−1 and 128.61 mAh·g−1 after 800 cycles at 1000 mA·g−1 in the voltage range of 3.0–4.6 V, while the Co3O4/RPC anode shows a high reversible capacity of 1081.33 mAh·g−1 after 100 cycles at 200 mA·g−1 and 901.09 mAh·g−1 after 400 cycles at 1000 mA·g−1. This work provides a new perspective for green engineering of both anodic and cathodic materials with enhanced lithium-ion storage performances derived from MOF-typed precursors.

Photocatalytic and antibacterial activity of green synthesized yttrium doped cobalt oxide nanoparticles using tender coconut water (Cocos nucifera)

Photocatalytic and antibacterial activity of green synthesized yttrium doped cobalt oxide nanoparticles using tender coconut water (Cocos nucifera)

Transition metal oxide catalytic abilities for fuel cell applications: Density functional theory (DFT) studies

Because of its heavy reliance on fossil fuels, the world's existing energy supply releases pollutants into the atmosphere. Researchers have conducted extensive studies on greener energy sources, particularly fuel cell technology, which generates power from electrochemical energy while emitting minimal carbon. But there are obstacles to fuel cell efficiency and commercialization, such as the slow oxygen reduction reaction (ORR) and the expensive and unstable platinum (Pt) catalysts used in fuel cell membranes. This work explores the use of tungsten oxide, cobalt, and titanium oxide nanoparticles as inexpensive, active electrocatalysts. Despite extensive research on the monoxides of these metals, their bimetallic compositions when combined with oxygen to function as fuel cell catalysts remain poorly understood. This work evaluates the catalytic capabilities of the crystallographic surfaces of these oxides using Density Functional Theory (DFT) via CASTEP and DMol3, as well as the Adsorption Locator module. These surfaces, which include CoWO4, Co3WO8, and TiWO4, have different levels of stability and reactivity when it comes to absorbing hydrogen and oxygen. This makes them potentially useful for changing the hydrogen oxidation and oxygen reduction reactions in fuel cells.

Constructing Co@C nanoparticles with chainmail-structure for highly efficient hydroformylation of 1-hexene

Constructing highly active noble-metal-free heterogeneous catalysts is the crux for the hydroformylation of long-chain α-olefins. Herein, novel chainmail-structured cobalt oxide nanoparticles (CoO@C|SBA-15) are fabricated by the channel confinement strategy, which display excellent activity for the 1-hexene hydroformylation. Specifically, the obtained catalyst shows 100% 1-hexene conversion and 94% heptanal selectivity, as well as up to 2.0 linear to branch (l/b) ratio, outperforming most of heterogeneous noble metal catalysts. Remarkably, in-situ DRIFT spectra combined with density functional theory calculations disclosed the metallic Co derived from in-situ reconstruction of CoO is the key active site for 1-hexene hydroformylation. Specifically, the reconstructed Co site is responsible for the adsorption of 1-hexene, and the graphite carbon layer promotes the adsorption of H2 and CO by interacting with the reconstructed Co. Moreover, the graphite carbon layer provides a strong protective effect on the internal cobalt active sites and thus enhances the catalytic stability during the harsh condition. This work provides a new method for designing the low-cost heterogeneous catalyst and emphasizes the intrinsic active sites for 1-hexene hydroformylation reaction.