Co3O4 Nanoparticles Research Articles

Synthesis of cobalt-oxide nanoparticles embedded in silicon nanotubes via low-energy cobalt implantation

Silicon nanotubes (Si NTs) show a unique structure compared to other silicon nanostructures, such as porous silicon, silicon nanoparticles, and silicon nanowires. Si NTs' well-defined structure in terms of silicon shell thickness, inner diameter, and length with a high surface area makes them useful in myriad applications. In this work, we fabricate Si NTs by using ZnO nanowires as templates; the Si NTs have a shell thickness of ∼13 nm, inner diameter of ∼80 nm, and a length in the range of 1–2 μm with embedded Co3O4 nanoparticles (NPs), which are formed by annealing the cobalt ion-implanted Si NTs. The cobalt ion implantation was carried out at 50 keV with a fluence of 7.5 × 1015 ions/cm2. The morphology and composition of the cobalt-NP decorated Si NTs are characterized by using scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), transmission electron microscopy (TEM), and x-ray photoemission spectroscopy (XPS). TEM, HRTEM, XPS, and Raman spectroscopy studies confirm the formation of Co3O4 nanoparticles in the NTs. The temperature-dependent zero-field-cooled (ZFC), and field-cooled (FC) magnetization for the Co implanted Si NTs before and after annealing is also measured and shows little magnetic response due to the low concentration of cobalt in the nanotubes. The fabrication process is compatible with the current semiconductor industry methods and may find potential applications in magnetic drug delivery and devices.

Modifying the aquatic toxicity of Co3O4 nanoparticles in exposed microalgae by CTAB mediated synthesis

Besides unique physical and chemical properties, Cobalt oxide nanoparticles (Co3O4 NPs) are ecotoxic in nature that limits their industrial applications. The present work assesses the ecotoxic effects of Co3O4 NPs in aquatic environments. Chlorella minutissima (freshwater microalgae) and Tetraselmis suecica (marine microalgae) were used as aquatic test species. Two forms of Co3O4 NPs were used; one was synthesized with CTAB (COCTAB NPs) and the other without CTAB (CO NPs). NPs were synthesized with the chemical co-precipitation method and further characterized. The average crystallite size of CO NPs and COCTAB NPs were 12–18 nm and 22–28 nm respectively. Aggregation occurred with both NPs but the increased hydrodynamic size was measured with COCTAB NPs in BG 11 (1465 nm) and f/2 media (1951 nm). The interaction of COCTAB NPs with microalgae showed a lower % growth inhibition effect than CO NPs. The 72 h EC 50 (effective concentration of a chemical having 50% of its impact) of COCTAB NPs for C. minutissima (50.71 mg/L) and T. suecica (63.92 mg/L) was higher than the corresponding EC 50 of CO NPs. Further, % chlorophyll – a content and % LDH (lactate dehydrogenase) release retained less affected in microalgae treated with COCTAB NPs. FTIR spectra and Zeta potential revealed that the use of CTAB in CO3O4 NPs synthesis has lowered toxicity possibly by preventing the cellular attachment of NPs and its ionic dissolution. The increased hydrodynamic size and colloidal instability also restricted the NPs from binding with cells crossing membrane barrier and causing any internal damage.

Coupling effect of Fe-doped Co3O4 nanoparticles with SrTiO3 nanotubes on the high-efficiency photocatalytic activities of basic violet 16 dye degradation and H2 evolution

The photocatalytic activity of semiconductors can be enhanced by doping with metal and/or nonmetal elements and coupling them with other semiconductors. Herein, highly ordered SrTiO3 nanotubes (NTs) and Fe-doped Co3O4 nanoparticles (NPs) were fabricated via the liquid phase deposition (LPD) process and the sol–gel method, respectively. Fe-doped Co3O4 NPs were assembled on the surface of SrTiO3 NTs to form heterostructured nanocomposites (NCs). The formation mechanism of SrTiO3 NTs and SrTiO3/Fe:Co3O4 NC was proposed, and the photocatalytic activity of the products was analyzed using basic violet 16 (BV16) dye as the pollutant and H2 evolution under visible light irradiation. The results showed that the SrTiO3/Fe:Co3O4 NC has the highest photocatalytic performance, with degradation rate of BV16 and H2 production rate of 1718 μmol.g−1.h−1, which was 13.2 and 2.8 times that of SrTiO3 NTs, respectively. The enhanced photocatalytic activity could be principally attributed to the improvement of charge separation resulting from the effects of doping Co3O4 NPs with Fe ions and their coupling with SrTiO3 NTs. The outstanding results using the SrTiO3/Fe:Co3O4 heterojunction exhibited its potential for the BV16 degradation and H2 production in environmental applications.

Surface immobilization mechanisms of cobalt ions on hydroxyapatite catalyst supports

Cobalt deposition in an excess of solution was used to design Co-modified hydroxyapatite materials with various Co loadings and controlled dispersion. It is rationalized how the properties of hydroxyapatite supports (more or less stoichiometric compositions, nanorod or platelet morphologies and crystalline (100) zig-zag termination or non-apatitic hydrated external layer), influence the immobilization processes of Co by operating either with slightly acidic (natural) or basic pH of the suspension media. Four cobalt immobilization mechanisms impacting the final dispersion of Co on hydroxyapatites were identified by combining structural (XRD, 1H and 31P solid-state NMR, UV-Vis, Raman and X-ray fluorescence spectroscopies), surface (XPS) characterizations of Co-modified hydroxyapatites after drying and thermal treatment at 500 °C, and monitoring of the pH and the composition of the supernatant solutions during the Co deposition step. On dried Co-modified crystalline stoichiometric hydroxyapatite nanorods, cobalt is highly dispersed through cationic exchange or strong electrostatic adsorption (SEA) at slightly acidic or basic pH, respectively. After thermal treatment at 500 °C, only cation exchange preserved atomic dispersion of Co(II) ions since Co3O4 nanoparticles were observed on samples for which Co deposition occurred via SEA. On defective hydroxyapatite platelets, cobalt deposited at acidic natural pH could diffuse in an external non-apatitic layer, whereas under basic pH media, this surface layer was hydrolysed, resulting in the formation of a cobalt-substituted hydroxyapatite layer in which only a limited fraction of the surface cobalt species could be probed by XPS.

Optimization strategy of Co3O4 nanoparticles in biomethane production from seaweeds and its potential role in direct electron transfer and reactive oxygen species formation

In the present study, three process parameters optimization were assessed as controlling factors for the biogas and biomethane generation from brown algae Cystoceira myrica as the substrate using RSM for the first time. The biomass amount, Co3O4NPs dosage, and digestion time were assessed and optimized by RSM using Box-Behnken design (BBD) to determine their optimum level. BET, FTIR, TGA, XRD, SEM, XPS, and TEM were applied to illustrate the Co3O4NPs. FTIR and XRD analysis established the formation of Co3O4NPs. The kinetic investigation confirmed that the modified model of Gompertz fit the research results satisfactorily, with R2 ranging between 0.989–0.998 and 0.879–0.979 for biogas and biomethane production, respectively. The results recommended that adding Co3O4NPs at doses of 5 mg/L to C. myrica (1.5 g) significantly increases biogas yield (462 mL/g VS) compared to all other treatments. The maximum biomethane generation (96.85 mL/g VS) was obtained with C. myrica at (0 mg/L) of Co3O4NPs. The impacts of Co3O4NPs dosages on biomethane production, direct electron transfer (DIET) and reactive oxygen species (ROS) were also investigated in detail. The techno-economic study results demonstrate the financial benefits of this strategy for the biogas with the greatest net energy content, which was 2.82 kWh with a net profit of 0.60 USD/m3 of the substrate and was produced using Co3O4NPs (5 mg/L).

Investigating the impact of electron beam irradiation on electrical, magnetic, and optical properties of XLPE/Co3O4 nanocomposites

Nowadays, many researchers aim to fill polymer materials with inorganic nanoparticles to enhance the polymer properties and gain the merits of the polymeric host matrix. Sol–gel synthesized Co3O4 nanoparticles are subjected to different doses of electron beam (10, 20, and 30 kGy) to study their physiochemical properties and choose the optimized nanoparticles to fill our polymeric matrix. Crosslinked polyethylene (XLPE) has been filled with 5 wt % of un-irradiated cobalt oxide nanoparticles using the melt extruder method. The structural, optical, magnetic, and electrical properties of the XLPE/Co3O4 nanocomposite before and after exposure to different doses of electron beam radiation have been characterized. The crystallite size of face-centered cubic spinel Co3O4 nanoparticles has been confirmed by XRD whereas and their unique truncated octahedral shape obviously appears in SEM micrographs. The crystallite size of Co3O4 nanoparticles has decreased from 47.5 to 31.5 nm upon irradiation at a dose of 30 kGy, and significantly decreased to 18.5 nm upon filling inside XLPE matrix. Related to the oxidation effect of the electron beam, the Co2+/Co3+ ratio on the surface of Co3O4 nanoparticles has decreased upon irradiation as verified by XPS technique. This consequently caused the partial elimination of oxygen vacancies, mainly responsible for the weak ferromagnetic behavior of Co3O4 in its nanoscale. This appears as decreased saturation magnetization as depicted by VSM. The XLPE/Co3O4 nanocomposite has also shown weak ferromagnetic behavior but the coercive field (Hc) has increased from 112.57 to 175.72 G upon filling inside XLPE matrix and decreased to 135.18 G after irradiating the nanocomposite at a dose of 30 kGy. The ionic conductivity of XLPE has increased from 0.133 × 10–7 to 2.198 × 10–3 S/cm upon filling with Co3O4 nanoparticles while a slight increase is observed upon irradiation.

Enriched performance of practical device assisted asymmetric supercapacitor: NiO/Co3O4 intercalated with rGO nanocomposite electrodes

In this present report, we developed high performance supercapacitor electrode material of NiO/Co3O4/rGO ternary nanocomposites synthesized by a hydrothermal method with a different nickel and cobalt molar proportions. The phase formation, surface morphology and elemental information studies of binary NiO/Co3O4 and ternary NiO/Co3O4/rGO nanocomposites were investigated. The electrochemical investigations of the binary and ternary nanocomposites electrodes have been examined. Compare with various molar proportions, the ternary NiO/Co3O4(1,3)/rGO nanocomposites shows an extraordinary capacitance value of 980 Fg−1 at 1 Ag−1 as well as robust cycle life (cyclic retention of 92 % over the 5000 cycles at 10 Ag−1). In 0–1.4 V, an asymmetric supercapacitor attained a specific capacitance of 87.2 Fg−1 and large power density (1396.3 W/kg) with extreme energy density (23.7 Wh/kg). Moreover, assembled device reveals a great rate capability (89 % over the 5000 cycles in the electrolyte of PVA-KOH). The ternary electrode has high capacitance, capacitance retention and large energy density due to NiO and Co3O4 nanoparticles being intercalated with the high surface of rGO, as well as the synergetic effect of NiO/Co3O4 and rGO.

Highly selective ion precipitation flotation for ternary Co–Zn–Mn separation: Stepwise chelation capture of Co and Zn from simulated zinc hydrometallurgy wastewater

Ion precipitation flotation technology was demonstrated to be an efficient method for the separation of valuable metals from low-concentration solution. However, the selective separation of three metals from mixing solution is a great challenge, and highly selective reagents are the key to polymetallic separation. In this work, stepwise separation of Co and Zn from the simulated zinc hydrometallurgy wastewater containing ternary Co–Zn–Mn metals by ion precipitation flotation process was proposed. It's demonstrated that organic reagents of 1-nitroso-2-naphthol (NN) and sodium dimethyldithiocarbamate (SDDC) had excellent selectivity for the capture of Co and Zn to form respective precipitate from wastewaters via the chelation reactions. After precipitation, dodecylpyridinium chloride (DPC) and tetradecyltrimethylammonium bromide (TTAB) were chosen as surfactants for the separation of Co and Zn sediments from the solution via the flotation process. The effects of solution pH, molar ratio, reaction temperature, and reaction time on the selective precipitation efficiencies of Co and Zn as well as the effects of surfactant dosage and flotation gas velocity on the flotation separation efficiencies were systematically investigated. It's demonstrated that the comprehensive recovery rates of Co, Mn, and Zn reach 98%, 90%, and 99%, respectively. After separation, oxidation calcination of the foam products was conducted to prepare high-purity Co3O4 and ZnO nanoparticles in which the organic matters were burnt out with gas emissions. The stepwise chelation capture mechanisms of Co and Zn by highly selective precipitation reagents were minutely discussed. It's demonstrated that the proposed selective stepwise precipitation and flotation method is suitable for recovery of critical metal ions from low-concentration polymetallic wastewaters.

Quantum capacitance induced by electron orbital reconstruction of g-C3N4/Co3O4 heterojunction: Improving electrochemical performance

Utilizing diverse material combinations in heterogeneous structures has become an effective approach for regulating interface characteristics and electronic structures. The g-C3N4/Co3O4 heterostructures were fabricated by uniformly modifying Co3O4 nanoparticles onto discrete clusters of g-C3N4 nanosheets. Then, they were subsequently employed as positive electrode materials for assembling hybrid supercapacitors. According to the first-principles calculation, Co3O4 and g-C3N4 formed Co-N ionic bonds, establishing interfacial space symmetry-broken heterojunction and direct exchange and superexchange between ions at the interface and sub-interface. This resulted in a high-density spin–orbit hybrid heterogeneous polarization interface, significantly improving the quantum capacitance of heterojunction materials. Experimental results showed that the heterojunction had a specific capacitance of 2662 F g−1 at 1 A g−1. When the power density was 750 W kg−1, the energy density reached 128 Wh kg−1. Even when the power density was 16850 W kg−1, it could show an energy density of 62.5 Wh kg−1. The g-C3N4/Co3O4 heterojunction could realize high energy density charge storage as the cathode material of supercapacitors. The construction of heterogeneous polarization interfaces for high-energy quantum capacitors provides a new and effective method for the energy storage field.

Impact of Co3O4 nanoparticles on epoxy's mechanical and corrosion-resistance properties for carbon steel in seawater

Co3O4 nanoparticles (Co3O4-NPs) are synthesized using the facile solvothermal method. FT-IR and XRD spectroscopic analyses verify the creation of cobalt oxide nanoparticles with an average size of 13.20 nm. Furthermore, Zeta potential assessments were carried out to identify the electrical charge of the surface of the produced Co3O4-NPs, which was found to be -20.5 mV. In addition, the average pore size of Co3O4-NPs is 19.8 nm, and their BET surface area is 92.4 m/g. The study also concerned the effect of Co3O4-NPs on epoxy's improvement of mechanical and corrosion protection for carbon steel in salt solution. By including Co3O4-NPs in an epoxy (EP) coating, corrosion is effectively prevented by non-permeable protective coatings that effectively reduce the transfer of corrosion ions and oxygen.

Construction of Hollow Ultrasmall Co3O4 Nanoparticles Immobilized in BN for CO2 Conversion.

Rational design and fabrication of metal-organic framework-derived metal oxide (MO) materials featuring a hollow structure and active support can significantly enhance their catalytic activity for specific reactions. Herein, a series of Co3O4 nanoparticles (NPs) immobilized in boron nitride (denoted as Co3O4@BN) with highly open and precisely controllable structures were constructed by an in situ self-assembly method combined with a controlled annealing process. The obtained Co3O4@BN not only possesses a hollow structure but also shows highly dispersed Co3O4 NPs and high loadings of up to 34.3 wt %. Owing to the ultrafine particle size and high dispersity, the optimized Co3O4@BN exhibits high catalytic activity for the cycloaddition of CO2 to epoxides under mild conditions (i.e., 100 °C and CO2 balloon), resulting in at least 4.5 times higher yields (99%) of styrene carbonate than that of Co3O4 synthesized by the pristine ZIF-67. This strategy sheds light on the rational design of hollow MO materials for various advanced applications.

Oxygen Reduction Pathway for Spinel Metal Oxides in Alkaline Media: An Experimentally Supported Ab Initio Study.

Precious-metal-free spinel oxide electrocatalysts are promising candidates for catalyzing the oxygen reduction reaction (ORR) in alkaline fuel cells. In this theory-driven study, we use joint density functional theory (JDFT) in tandem with supporting electrochemical measurements to identify a novel theoretical pathway for the ORR on cubic Co3O4 nanoparticle electrocatalysts, which aligns more closely with experimental results than previous models. The new pathway employs the cracked adsorbates *(OH)(O) and *(OH)(OH), which, through hydrogen bonding, induce spectator surface *H. This results in an onset potential closely matching experimental values, in stark contrast to the traditional ORR pathway, which keeps adsorbates intact and overestimates the onset potential by 0.7 V. Finally, we introduce electrochemical strain spectroscopy (ESS), a groundbreaking strain analysis technique. ESS combines ab initio calculations with experimental measurements to validate the proposed reaction pathways and pinpoint rate-limiting steps.

Core‐shell Co3O4@CoO Nanoparticles for Enhanced OER Activity

AbstractCore‐shell Co3O4@CoO nanoparticles were prepared by calcination of rock‐salt CoO and fully characterized by PXRD, TEM and XPS measurements. XPS studies showed that the Co(III) cation concentration steadily increased and the OER activity of the resulting core‐shell Co3O4@CoO nanoparticles decreased with increasing calcination time, which was attributed to the increasing presence of catalytically inactive Co(III) cations. The decrease in OER activity was also observed for untreated CoO nanoparticles (1) after chronopotentiometric (CP) treatment at 10 mA cm−2 for 18 h. The IR and EEL spectra of the resulting nanoparticles are comparable to those of a fully oxidized Co3O4 sample (1–300), that was prepared by calcining of the CoO sample (1) for 1 h at 300 °C.

A Hybrid Synthesis Approach: Tailoring Photocatalytic Activity of Co3O4 Nanoparticles by PEG Functionalization

This study presents a novel fusion of precipitation and hydrothermal methods for the synthesis of polyethylene glycol (PEG)-functionalized cobalt oxide (Co3O4) nanoparticles. The synthesized PEG/Co3O4 nanoparticles characterized using various techniques to elucidate their structure, composition, properties and application. The XRD analysis confirmed the formation of cubic phase of Co3O4 with a crystallite size of 2.04 nm. Two direct bandgap (Eg) transitions were observed at energy levels of 1.68 and 2.5 eV, exhibiting intensities that exceeded those reported in prior studies. The synthesized nanoparticles exhibited distinct structural features as revealed by FESEM and HRTEM investigations. Furthermore, the FTIR analysis provided evidence of interactions between PEG and Co3O4, suggesting successful functionalization. The high crystallinity of the PEG-mediated Co3O4 nanoparticles was further confirmed by the selected area electron diffraction (SAED) pattern. The XPS analysis revealed the presence of Co2+ and Co3+ ions, along with defect sites, confirming the successful synthesis of Co3O4 NPs with controlled oxidation states. These findings offer valuable insights into the chemical composition and electronic structure of the synthesized PEG-mediated Co3O4 nanoparticles. The photocatalytic activity of the PEG/Co3O4 nanoparticles was evaluated through the degradation of Congo red dye, a typical azo dye pollutant. The study revealed that PEG/Co3O4 (dose 200 mg L-1) acted as an efficient photocatalyst for Congo red degradation. These results suggest that PEG-mediated Co3O4 nanoparticles hold promising potential as efficient photocatalysts for the treatment of wastewater containing organic contaminants.

Construction of highly sensitive electrochemical immunosensor based on Au and Co3O4 nanoparticles functionalized Ni/Co bimetal conductive MOF for quantitative detection of HBsAg

Herein, highly sensitive electrochemical immunosensor based on noble metal and metal oxide nanoparticles functionalized bimetal conductive metal–organic frameworks (c-MOFs) was proposed toward HBsAg detection. The nanorod-like architecture of Ni3(HITP)2c-MOFs was synthesised via a simple and facile route, followed by dopant coble ions formation cobaltosic oxide (Co3O4) nanoparticles decorated bimetal NiCo(HITP) c-MOFs nanocomposites. Benefiting from large specific surface area, high electrical conductivity and abundant active sites of desirable nanostructures, the resultant Co3O4NPS/NiCo(HITP) bimetal c-MOFs nanostructure exhibits fast electron transfer capability and effective specific binding between antigen and antibody. Meanwhile, different amounts of Au nanoparticles were further functionalized on Co3O4NPS/NiCo(HITP) nanocomposites to further improve the electrochemical properties. Under optimum condition, the as-proposed Au@Co3O4NPS/NiCo(HITP) electrochemical immunosensor exhibits superior sensing performances toward HBsAg including wide linear response range from 1 pg mL−1 to 100 ng mL−1 and low detection limit of 15 fg mL−1 (S/N = 3). Meanwhile, the as-fabricated electrochemical immunosensors also displays outstanding selectivity, repeatability and stability. Besides, quantitative detection of HBsAg also achieves satisfactory results in real sample detection. Thereby, our work not only provides a promising strategy to construct highly sensitive electrochemical immunosensor using hybrid c-MOFs nanomaterials but also presents a potential application in the early diagnosis of hepatitis B-related diseases.

Micromolar Levofloxacin Sensor by Incorporating Highly Crystalline Co3O4 into a Carbon Paste Electrode Structure

In this work, we successfully prepared a modified cobalt oxide (Co3O4) carbon paste electrode to detect Levofloxacin (LEV). By synthesizing Co3O4 nanoparticles through the chemical coprecipitation method, the electrochemical properties of the electrode and LEV were thoroughly investigated using CV, SWV, and EIS, while material properties were scrutinized using ICP-OES, TEM, SEM, and XRD. The results showed that the prepared electrode displayed a better electrocatalytic response than the bare carbon paste electrode. After optimizing SWV, the electrode exhibited a wide linear working range from 1 to 85 μM at pH 5 of BRBS as the supporting electrolyte. The selectivity of the proposed method was satisfactory, with good repeatability and reproducibility, strongly suggesting a potential application for determining LEV in real samples, particularly in pharmaceutical formulations. The practicality of the approach was demonstrated through good recoveries, and the morphology of the materials was found to be closely related to other parameters, indicating that the developed method can provide a cost-effective, rapid, selective, and sensitive means for LEV monitoring. Overall, this project has made significant progress towards developing a reliable method for detecting LEV and has opened up new opportunities for future research in this field.

Laser assisted oxygen vacancy engineering on Fe doped CoO nanoparticles for oxygen evolution at large current density

Exploring cost-effective non-noble metal-based catalysts with high activity and stability is of great significance for energy conversion and storage involving oxygen evolution reaction (OER). Here, we employed a laser irradiation technique to synthesis Fe doped CoO nanoparticles with ultrafine size (≈ 5.4 nm) and abundant oxygen vacancies (Fe-Ov-CoO). The ultrafine size of Fe-Ov-CoO nanoparticles provides more active sites to be exposed. Fe doping and oxygen vacancy promote the intrinsic activity and electron transfer rates of Fe-Ov-CoO, giving rise to high activity and stability catalyst for OER. Fe-Ov-CoO delivers a large current density of 1000 mA cm−2 at an overpotential of 548 mV, which is much better than commercial RuO2. Moreover, Fe-Ov-CoO presents a remarkable long-term stability with negligible degeneration at a high current density of 500 mA cm−2 for 120 h. This work provides a new route to develop OER electrocatalyst with high activity and stability.

A green synthetic method for cobalt(II,III) oxide nanoparticles with high surface activity

Objectives. To develop a new green method for the synthesis of nanosized materials of cobalt(II,III) oxide, with improved surface activity, using environmentally friendly precursors and solvents.Methods. A green method was proposed, in order to isolate Co3O4 nanoparticles with high surface activity. Instead of the usual organic solvents, three different natural sugars, including glycogen, sucrose, and glucose were used for the first time as templates. Water as a green solvent was used in all the steps. The polymorphic composition of the synthesized samples was determined by means of X-ray phase analysis. The morphology of the obtained crystallites was studied from micrographs of the oxide phases. Image Pro Plus 6 software was used to measure the size of nanoparticles. The surface activity of the isolated samples was studied using the Brunauer–Emmett–Teller method and the Langmuir method. The Barret–Joyner–Halenda method was used to determine the diameter, volume, and distribution of pores.Results. The crystallite sizes of the samples are 23 nm, 36 nm, and 30 nm for glucose, glycogen, and sucrose templates, respectively. Adsorption–desorption isotherms for samples obtained from complexes of glucose and sucrose correspond to type IV, indicating a strong interaction between the adsorbent and the adsorbed sample. The isotherm for the sample isolated from the complex with glycogen is of a different type and most likely indicates that this sample is almost completely mesoporous. The pore radii are found in the interval 1.2–1.6 nm.Conclusions. A new green method for the synthesis of nanosized particles of Co(II,III) oxide using natural saccharides and deionized water was developed. The composition, morphology, structure, and surface activity of the samples obtained were studied. It was shown that due to the polymeric structure of their metal complexes and the ability to bind active carbon on the surface of nanoparticles, natural saccharides can be used as matrices in the synthesis of nanosized metal oxides with high surface activity.

Symmetric supercapacitor based on Co3O4 nanoparticles with an improved specific capacitance and energy density

Metal oxides have garnered significant research interest as highly effective electrode materials for supercapacitors. In this study, we synthesized Co3O4, an electrode material for supercapacitors, utilizing an in-situ hydrothermal method with varying pH levels in the precursor solution. The obtained samples underwent through structural, optical, surface morphological, electrical, and electrochemical analyses, affirming their exceptional suitability for supercapacitor applications. The influence of pH fluctuations in the synthesis process, on the specific capacitance values were analyzed. The X-ray diffraction pattern and Raman spectrum confirmed the normal cubic spinel structure of Co3O4 nanoparticles. The X-ray photoelectron spectrum revealed the chemical bond states of Co3O4. The optical bandgap have been investigated from the Tauc plot. The surface area and morphology were determined through Brunauer Emmett and Teller method and field emission scanning electron microscope images. A high specific capacitance of 1195.05 Fg−1 at a current density of 1.5 Ag−1 was obtained in the three-electrode study for the sample synthesized at a pH of 10. A symmetric supercapacitor (SSC) device was fabricated to facilitate practical analysis. The symmetric supercapacitor device demonstrated a notably elevated specific capacitance of 870.6 Fg−1 at an operational current density of 5 Ag−1, concurrently achieving an enhanced energy density of 77.3 W h/kg and superior power density of 1997.7 W/kg. These performance metrics surpassed those of prior studies in the field. Furthermore, the SSC device exhibited an excellent cyclic stability of 88 % after undergoing 970 charge/discharge cycles. As a result, Co3O4 emerges as a promising and efficient electrode material for applications in supercapacitors.

Preparation of Co3O4 Nanoparticles in a Lyotropic Liquid Crystal Medium and Their Application in Anti-bacterial, Anti-cancer and Catalytic Activities

Preparation of Co3O4 Nanoparticles in a Lyotropic Liquid Crystal Medium and Their Application in Anti-bacterial, Anti-cancer and Catalytic Activities