Co3O4 Particles Research Articles

Room temperature xylene sensor based on Co3O4/GF hybrid

Sensitive Xylene solid-state gas sensor based graphene foam decorated with cobalt oxide has been successfully fabricated via a simple impregnation method. The structure and surface morphological analysis carried out using multiple techniques including XRD, SEM, Raman, TGA, BET, and BJH. The morphological examination using SEM confirmed that spherical CO3O4 particles fully covered both the outer surface and interior pores of GF. Raman analysis confirmed that both characteristic bands for carbon nanomaterials are absent. The specific surface area was estimated using the BET method to be 543.254 m²/g which is a relatively high value. The prepared sensors showed a good response towards xylene. Moreover, we examine the sensitivity of the CO3O4/GF sensor to detect other volatile organic compounds, such as methanol, ethanol, toluene, and heptane, demonstrating that the CO3O4/GF sensor exhibits excellent sensitivity to xylene (detection limit = 0.5 ppm) at room temperature.

In situ decoration of nanosized metal oxide on highly conductive MXene nanosheets as efficient catalyst for Li-O2 battery

Abstract Combining nanomaterials with complementary properties in a well-designed structure is an effective tactic to exploit multifunctional, high-performance materials for the energy conversion and storage. Nonprecious metal catalysts, such as cobalt oxide, with superior activity and excellent stability to other catalysts are widely desired. Nevertheless, the performance of CoO nanoparticles as an electrode material were significantly limit for its inferior conductivity, dissolution, and high cohesion. Herein, we grow ultrafine cobalt monoxide to decorate the interlayer and surface of the Ti3C2Tx nanosheets via a hydrothermal method companied by calcination. The layered MXenes act as the underlying conductive substrate, which not only increase the electron transfer rate at the interface but also greatly improve the electrochemical properties of the nanosized CoO particles by restricting the aggregation of CoO. The resulting CoO/Ti3C2Tx nanomaterial is applied as oxygen electrode for lithium-oxygen battery and achieves more than 160 cycles and first cycle capacity of 16,220 mAh g−1 at 100 mA g−1. This work paves a promising avenue for constructing a bi-functional catalyst by coupling the active component of a transition metal oxide (TMO) with the MXene materials in lithium-oxygen battery.

Effect of Mn and reduced graphene oxide for the Fischer–Tropsch reaction: an efficient catalyst for the production of light olefins from syngas

In this work, we demonstrate an efficient and high-performance catalyst for the production of light olefins from synthesis gas employing manganese (Mn)-mediated graphene oxide. First the CO hydrogenation reaction was catalyzed using bimetallic alumina supported-cobalt-manganese catalysts with various ratio of cobalt to Mn (1:1, 1:2, 1:3, 2:1 and 3:1). After the determination of the effect of different ratios on C2–C4 light olefin production, the efficiency of nanoporous graphene and reduced graphene oxide as support at an optimum ratio of bimetallic Co–Mn/Al2O3 catalyst were evaluated. The catalysts were characterized by BET, TPR, FTIR, RAMAN, TGA, XRD, FESEM, ICP, and XPS measurements. The reactions carried out in a fixed bed reactor under the constant condition (320 °C, atmospheric pressure, H2/CO = 1). It was identified that light olefin selectivity of the catalysts varies with different ratios. By increasing of the amount of Mn up to 1, methane formation decreased and light olefin selectivity increased. Conversely, with the further increase of the amount of Mn, light olefin selectivity decreases. This phenomenon is attributed to varying the degrees of Mn incorporation in the Co3O4 particles, which causes different degrees of reduction limiting the available metallic Co surface area. Also, the advantages of reduced graphene oxide supported nanoparticles (NPs) included higher conversion and C2–C4 light olefin selectivity in comparison with the graphene supported catalyst. The obtained results from the TPR revealed that the NPs reducibility was higher for the RGO supported catalyst. An increase of selectivity and conversion of Co–Mn/RGO catalyst is likely due to altering the surface interactions of NPs with the functional groups on reduced graphene oxide which was confirmed with XPS, FTIR and Raman analyses.

Highly stable bifunctional catalyst for Zn-Air batteries: The effect of a nitrated carbon support on Co3O4 activity

The use of Co3O4 as electrocatalyst in Zn-air batteries has been extensively studied. However, electrical rechargeability has only been achieved by combining metal oxides with precious metals or using a second electrode/electrolyte to promote the oxygen evolution reaction. In this work, we report efficient catalytic activity of Co3O4 for both, the oxygen reduction and oxygen evolution reaction by fusing Co3O4 particles to a nitrated carbon support. The functionalized carbon matrix improves not only the carbon wettability, but also provides acidic sites and carbon-containing functional groups. This synergistic configuration enhances the reaction kinetics especially for the oxygen evolution reaction. The electrochemical characterization demonstrated lower overpotential and higher stability over 160 cycles for the Co3O4 catalyst attached to the nitrated carbon matrix compared to the pristine carbon matrix. Electrochemical impedance spectroscopy demonstrated 21 times lower degradation for the functionalized air-cathode at 2 mA cm−2, 12.4 times lower degradation at 5 mA cm−2, and 1.15 times lower degradation at 10 mA cm−2. Although further work is required, the low-cost process and the electrochemical performance of this catalyst represent considerable progress towards the development of rechargeable and flexible Zn-air batteries.

Effect of Magnetic Co–CoO Particles on the Carrier Transport in Monolayer Graphene

Electrodeposition of cobalt on monolayer graphene synthesized by chemical vapor deposition produces Co–CoO/graphene composite structures, which is accompanied by increases in the electrical resistance and magnetoresistance. We show that the observed magnetoresistance effect is caused by two competing contributions: negative (NMR) and positive (PMR) magnetoresistance. In weak magnetic fields, the NMR is described by quantum localization correction to the Drude model of conductivity in graphene. The enhancement of PMR observed in strong magnetic fields is related to the Lorentz mechanism in Co–CoO particles.

Highly porous cobalt oxide-decorated carbon nanofibers fabricated from starch as free-standing electrodes for supercapacitors

Hybrid supercapacitor with improved energy density was prepared by electrospinning using biopolymer, and a simple dip-coating method. Through the optimization of the dip-coating time and post-heat treatment process, carbon nanofiber with highly porous structure and Co3O4 particles formed on the surface was successfully fabricated. It was found that Co3O4/C nanofibers dipped for one hour exhibited a highly porous microstructure with a specific surface area of 964 m2/g, and this was mainly composed of pores with an average diameter of 2.4 nm. These characteristics contributed to superior electrochemical properties of hybrid nanofibers, among which a 137 F/g specific capacitance was achieved with a very stable cycle life (91% retention after 5,000 cycles). The combination of porous carbon nanofiber derived by optimized calcination process of Co precursor and redox reaction from the Co3O4 provided a synergistic effect for enhanced specific capacitance of the hybrid supercapacitor.

Synthesizing Co3O4-BiVO4/g-C3N4 heterojunction composites for superior photocatalytic redox activity

In this study, a novel coral-like Co3O4-BiVO4/g-C3N4 ternary composite catalyst was successfully synthesized via high temperature polymerization and controlled hydrothermal reaction. In the Co3O4-BiVO4/g-C3N4 ternary hybrid system, the bulk Co3O4 particles were uniformly dispersed on the coral-like BiVO4 nanosheet, which not only enhanced to increase the response range and absorption to visible light, also contributed to suppress the recombination of photogenerated electron holes. The introduction of flocculent g-C3N4 increased the specific surface area of the catalytic system while accelerating the transmission efficiency of photogenerated carriers. After being illuminated for 90 min under the visible light, the degradation efficiency of pure BiVO4 and g-C3N4 catalysts were 81% and 80.2%, respectively. And the two binary catalysts, Co3O4-BiVO4 and BiVO4/g-C3N4 composite catalyst, performed the higher photocatalytic activity, which reached 94.8% and 96.8%, while ternary catalyst Co3O4-BiVO4/g-C3N4 composite catalyst showed the highest photocatalytic activity, the removal rate of KN-R was up to 99.6% after being irradiated for only 30 min with visible-light. Even more, its optical and electrochemical properties were greatly improved, making it as a forceful candidate for practical photocatalysts under visible light. In summary, this work not only provided a highly efficient heterojunction-structured visible-light photocatalyst, but also supplied a novel method to diminish the photo-carriers recombination.

Unique Double Carbon Protection Structured Co<sub>3</sub>O<sub>4</sub> Anode for Lithium Ion Battery

In this study, novel Carbon aerogel (CA)/Co3O4/Carbon (C) composites with a double protective structure are synthesized through a solvothermal method and in-situ polymerization. The morphology and structure are characterized by X-ray diffraction, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and Fourier transform infrared spectroscopy (FTIR). The loading content of active anode material Co3O4 in the composite is investigated by thermogravimetry, and the electrochemical properties of the composite are characterized by electrochemical impedance spectroscopy (EIS). The SEM results show that the nano-sized spherical Co3O4 particle is adhered to the inner Carbon aerogel (CA). The HRTEM result indicates the thickness of the prepared Carbon (C) up to 40 nm. Nano-sheet is coated on the surface of the Co3O4 particle. Compared with the pure Co3O4 anode materials, the Carbon aerogel (CA)/Co3O4/Carbon (C) composites have better transport kinetics for both electron and lithium-ion in EIS testing results, which may contribute to its higher specific capacity and higher first coulomb efficiency. Due to the unique structure of the composite material with double protection against the volume expansion of Co3O4 when charged, the Carbon aerogel (CA)/Co3O4/Carbon (C) composite material exhibits better cycle stability with a discharge capacity of 1180 mAh/g after 50 cycles. Therefore, the double protection strategy is verified as an effective method to improve the electrochemical performance of transition metal oxide with carbon composite as an anode material in lithium battery.

A bio-inspired nanofibrous Co3O4/TiO2/carbon composite as high-performance anodic material for lithium-ion batteries

A bio-inspired nanofibrous Co3O4/TiO2/carbon composite was fabricated using natural cellulose substrate (laboratory filter paper) as both the carbon source and the structural scaffold. Employing a surface sol–gel process to form a thin TiO2 gel layer coating on each cellulose nanofiber of the filter paper, the resulted composite sheet was successively carbonized in inert atmosphere to give a nanofibrous TiO2/carbon composite; afterwards, nano-sized Co3O4 particles (10–30 nm) were uniformly deposited onto the yielded composite fibers via a simple hydrothermal method, resulting in the Co3O4/TiO2/carbon hybrid. The ternary composite possessed a unique hierarchically three-dimensional porous structure which inherited precisely from the initial filter paper. This special structure with the internal conductive carbon fiber and the external nano-sized Co3O4 particles offered the nanocomposite with an excellent electrochemical performance as anodic material for lithium-ion batteries. The optimal sample with a Co3O4 mass content of 50.6% delivered an initial discharge capacity of 1239 mAh g−1 at a current density of 100 mA g−1, which was far exceeded the theoretical capacity of Co3O4. The extra capacity is ascribed to the additional lithium storage sites provided by the large specific surface area of the composite, and the formation of the solid electrolyte interface (SEI) layer in the initial discharge process causing a large consumption of Li+ which results in some irreversible capacity. And after 200 discharge/charge cycles, a high reversible capacity of 764 mAh g−1 was maintained, which is higher than most of the Co3O4/carbon hybrid materials reported. This work provided a simple and efficient strategy for designing and preparing nanoscale metal-oxide/carbon composite material with considerable potential in energy storage and conversion.

Novel core-shell nanocomposites based on TiO2 -covered magnetic Co3 O4 for biomedical applications.

Magnetic Co3 O4 nanoparticles (NPs) have great potential for applications in biomedicine, as contrast enhancement agents for magnetic resonance imaging, or for drug delivery. Although these NPs are so attractive, their potential toxicity raises serious questions about decreasing cellular viability. In this context, Co3 O4 NPs were prepared via sol-gel method and encapsulated with a layer of TiO2 , a biocompatible oxide, and subjected to structural, magnetic and toxicity characterization. X-ray diffractograms of the samples demonstrate the successful synthesis of the spinel and Raman spectroscopy confirms the coating of the Co3 O4 spinel with TiO2 . The Co3 O4 cores showed a very intense superparamagnetic character; however, this behavior is strongly suppressed when the material is covered with TiO2 . According to the neutral red uptake assay, the coating of the cores with TiO2 significantly decreases the cytotoxic character of the Co3 O4 particles and, as it can be observed with the zeta (ξ) potential measurements, they form a stable colloidal dispersion at cytoplasmic pH. The effect of the thermal treatment enhances the biocompatibility even further, with no statistically significant effect on cell viability even at the highest analyzed concentration. The proposed pathway presents a successful sol-gel method for the preparation of Co3 O4 @TiO2 core-shell nanoparticles. This work opens up possibilities for future application of these materials not only for magnetic resonance imaging but also in catalysis and hyperthermia.

Sandwich-Like Co₃O₄/Graphene Nanocomposites as Anode Material for Lithium Ion Batteries.

In this work, sandwich-like Co₃O₄/graphene nanocomposites were synthesized by a facile hydrothermal process and subsequent thermal treatment. X-ray diffraction and scanning electron microscopy analyses were employed to characterize crystalline structural and morphology. Results demonstrated that approximately 150 nm Co₃O₄ particles were dispersed among the graphene sheets. The graphene not only enhanced the conductivity of Co₃O₄/graphene nanocomposites but also improved the structural stability of Co₃O₄ nanoparticles. As an anode material for lithium-ion batteries (LIBs), the Co₃O₄/graphene nanocomposites exhibited excellent electrochemical performance, higher rate capability, and longer cycle life than pristine Co₃O₄. The Co₃O₄/graphene nanocomposites maintained a specific capacity of 639.8 mAhg-1 at a current density of 0.5C (1C = 890 mAg-1) after 50 cycles with capacity retention rate of 71%. Co₃O₄/graphene nanocomposites also exhibited excellent rate performance with a discharge capacity of 676.5 mAh g-1 at a current density of 2C. Overall, the sandwich-like Co₃O₄/graphene nanocomposites are good candidate materials for high-capacity anode for LIBs.

Heterogeneous activation of peroxymonosulfate by a biochar-supported Co3O4 composite for efficient degradation of chloramphenicols

Herein, a new peroxymonosulfate (PMS) activation system was established using a biochar (BC)-supported Co3O4 composite (Co3O4-BC) as a catalyst to enhance chloramphenicols degradation. The effects of the amount of Co3O4 load on the BC, Co3O4-BC amount, PMS dose and solution pH on the degradation of chloramphenicol (CAP) were investigated. The results showed that the BC support could well disperse Co3O4 particles. The degradation of CAP (30 mg/L) was enhanced in the Co3O4-BC/PMS system with the apparent degradation rate constant increased to 5.1, 19.4 and 7.2 times of that in the Co3O4/PMS, BC/PMS and PMS-alone control systems, respectively. Nearly complete removal of CAP was achieved in the Co3O4-BC/PMS system under the optimum conditions of 10 wt% Co3O4 loading on BC, 0.2 g/L Co3O4-BC, 10 mM PMS and pH 7 within 10 min. The Co3O4/BC composites had a synergistic effect on the catalytic activity possibly because the conducting BC promoted electron transfer between the Co species and HSO5− and thus accelerated the Co3+/Co2+redox cycle. Additionally, over 85.0 ± 1.5% of CAP was still removed in the 10th run. Although both SO4− and OH were identified as the main active species, SO4− played a dominant role in CAP degradation. In addition, two other chloramphenicols, i.e., florfenicol (FF) and thiamphenicol (TAP), were also effectively degraded with percentages of 86.4 ± 1.3% and 71.8 ± 1.0%, respectively. This study provides a promising catalyst Co3O4-BC to activate PMS for efficient and persistent antibiotics degradation.

Enhanced photocatalytic hydrogen production over Co3O4@g-C3N4 p-n junction adhering on one-dimensional carbon fiber

Photocatalytic hydrogen production from water using photocatalysts is a desirable method to produce renewable energy. Specifically, combining multiple semiconductors to separate charges effectively is an achievable way to improve photocatalytic hydrogen production. In this study, a novel photocatalyst which tricobalt tetraoxide (Co3O4) modified graphitic carbon nitride (g-C3N4) nanosheets and at the same time their adhered to one-dimensional carbon fibers (CNFs) carrier (denoted as Co3O4@g-C3N4/CNFs) was successfully prepared. The single CNFs was obtained by electrospinning technique and high temperature calcination. The g-C3N4/CNFs was fabricated through the vapor deposition method. After that, the Co3O4@g-C3N4/CNFs photocatalyst was successfully composed with the hydrothermal treatment of cobalt chloride hexahydrate and roasting technology under air condition. In addition, the photoactivity of the catalysts was evaluated by hydrogen production from photocatalytic water splitting, and the result showed that the hydrogen evolution rate was in the following order: Co3O4@g-C3N4/CNFs composite > g-C3N4/CNFs. The composite of Co3O4@g-C3N4/CNFs exhibited a hydrogen production rate of 67.17 μmol g−1 h−1, while the rate for hydrogen production of g-C3N4/CNFs was 49.67 μmol g−1 h−1. It was known that the Co3O4 particles which were uniformly dispersed on the surface of g-C3N4/CNFs efficiently enhanced separation photo-generated electron-hole pairs, thus improving the visible-light photocatalytic activity.

Effect of sodium lauryl sulphate on microstructure, corrosion resistance and microhardness of electrodeposition of Ni–Co3O4 composite coatings

Ni–Co3O4 composite coatings were electrodeposited on mild steel surface from a Watts-type bath in the presence of sodium lauryl sulfate (SLS). The dispersed Co3O4 particles in the presence of SLS have a greater tendency to move towards cathode and get incorporated in the coating. SLS modifies chemical composition, surface morphology and microstructure of the Ni–Co3O4 composite coating. The developed composite coating exhibits higher corrosion resistance and microhardness than the pure nickel coating. The loadings of bath solution with different concentrations of Co3O4 particles in the presence of SLS provide hydrophobic nature to the coating surface, which is much effective in enhancing the corrosion resistance of Ni–Co3O4 composite coating. The agglomeration of Co3O4 particles (>3 g/L) under high bath load condition develops defects and dislocation on the coating surface, which results in lower corrosion resistance of the deposit. The mechanical properties of the hydrophobic coatings were assessed by the linear abrasion test.

The effect of calcination's temperature on the structural, morphological, optical behaviour, hemocompatibility and antibacterial activity of nanocrystalline Co3O4 powders

Nanocrystalline Co3O4 powders have been successfully prepared by using the precipitation method. The novelty in the present work is the comparative investigation of the influence of the calcination temperatures on the structural, morphological, optical, hemocompatible and antibacterial properties of nanocrystalline Co3O4 powders. The Powder X-ray Diffraction (XRD) pattern result displays single phase Co3O4 particles well crystalline in nature. The Scanning Electron Microscopy (SEM) result shows the agglomerated spherical Co3O4 particles increasing with increase of calcination temperatures. The particle size and morphology of the Co3O4 samples are characterized by using the Transmission Electron Microscopy (TEM) analysis. The optical absorption, optical band gap, and charge transfer between cobalt and oxygen are obtained from the UV–visible spectra. The fluorescence (FL) emission spectra reveal that strong visible emission peaks are observed at 402 and 414 nm for the Co3O4 nanoparticles calcined at 450 and 600 °C, respectively. The hemolysis result reveals their highly hemocompatible nature. The antimicrobial activity of the samples against the gram negative bacteria Escherichia coli (E.coli) has been investigated. In addition, the possible mechanisms of hemocompatibility and antimicrobial activity of the Co3O4 nanoparticles have been investigated in this current work.

Microstructures and electrochemical properties of Co3O4 anodes coated by silane coupling agents

The surface of a Co3O4 anode for lithium ion batteries (LIBs) was treated by a facile solid-state method using a silane coupling agent. Characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) mapping, and transmission electron microscopy (TEM) indicate that amorphous SiO2 with an average thickness of 5–8 nm was uniformly coated on the surfaces of Co3O4 particles. The SiO2 coating did not induce any change in the crystal lattice and morphology, but reduced the crystallite size of Co3O4 slightly. Electrochemical tests demonstrate that the electrochemical performances of the Co3O4 anode were significantly improved by coating with 2 wt% SiO2. Specifically, when coated with 2 wt% SiO2 using a silane coupling agent, the charge capacity of pure Co3O4 under a constant current density of 50 mA g−1 was increased to 169.54 and 183.09 mA h g−1 at room temperature (RT) and 55 °C, respectively, and improved by 1.99 and 2.68 times under a high current density of 800 mA g−1 at RT and 55 °C respectively. Furthermore, the charge capacity of coated Co3O4 was 1.35 times higher than that of the untreated material after 50 cycles at 55 °C. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests showed that the improved performance is mainly due to the unique coating layer of amorphous SiO2 on the surface, which effectively reduces the direct contact between the anode material and the electrolyte and suppresses the side reactions between Co3O4 and the electrolyte.

Cobalt Oxide Catalysts in the Form of Thin Films Prepared by Magnetron Sputtering on Stainless-Steel Meshes: Performance in Ethanol Oxidation

Catalytic total oxidation is an effective procedure to minimize emissions of volatile organic compounds (VOC) emissions in industrial gases. Catalysts in the form of meshes are remarkable as they minimize the internal diffusion of reactants during the reaction as well as the need of expensive active components. In this paper, various conditions of radio frequency magnetron sputtering of cobalt on stainless-steel meshes was applied during catalyst preparation. Properties of the supported Co3O4 catalysts were characterized by SEM, XRD, temperature programmed reduction (H2-TPR), FTIR, XPS, and Raman spectroscopy. Catalytic activity was examined in deep oxidation of ethanol chosen as a model VOC. Performance of the catalysts depended on the amount of Co3O4 deposited on the supporting meshes. According to specific activities (the amounts of ethanol converted per unit weight of Co3O4), smaller Co3O4 particle size led to increased catalytic activity. The catalyst prepared by sputtering in an Ar+O2 atmosphere without calcination showed the highest catalytic activity, which decreased after calcination due to enlargement of Co3O4 particles. However, specific activity of this catalyst was more than 20 times higher than that of pelletized commercial Co3O4 catalyst used for comparison.

Role of Lattice Oxygen in the Oxygen Evolution Reaction on Co3O4: Isotope Exchange Determined Using a Small-Volume Differential Electrochemical Mass Spectrometry Cell Design

This work demonstrates the roleof lattice oxygen of metal oxide catalysts in the oxygen evolution reaction (OER) as evidenced by isotope labeling together with the differential electrochemical mass spectrometry (DEMS) method. Our recent report assessed this role for Co3O4 using a flow-through DEMS cell, which requires a large volume of electrolyte. Herein, we extend this procedure to different Co3O4 catalyst loadings and particle sizes as well as the mixed Ag + Co3O4 catalyst. We introduce, for the first time, a novel small-volume DEMS cell design capable of using disc electrodes and only <0.5 mL of electrolyte. The reliability of the cell is demonstrated by monitoring gas evolution during OER in real time. This cell shows high sensitivity, high collection efficiency, and very short delay time. DEMS results reveal that only the interfacial part (∼0.2% of the total loading or 25% of surface atoms) of the catalyst is active for OER. Interestingly, the amount of oxygen exchanged on the mixed Ag + Co3O4 catalyst is higher than that on the single Co3O4 catalyst, which illustrates the improved electrocatalytic activity previously reported on this mixed catalyst. Furthermore, the real surface area of the catalysts is estimated using different methods (namely, the ball model, double layer capacitance, isotope exchange, and redox peak methods). The surface areas estimated from the Brunauer-Emmett-Teller (BET) and ball models are comparable but roughly three times higher than that of the redox peak method. Our method represents an alternative approach for probing the mechanism and real surface area of catalysts.

Co single-atom anchored on Co3O4 and nitrogen-doped active carbon toward bifunctional catalyst for zinc-air batteries

Highly efficient noble-metal-free electrocatalysts are urgently explored for high energy density and safe metal-air batteries. Herein, an ingenious Co-Co3O4@NAC is prepared for this purpose by anchoring Co single atom on both Co3O4 nanoparticle and nitrogen-doped active carbon (NAC), where synergistic interaction among Co atoms, Co3O4 particles and NAC plays a significant role for excellent oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Moreover, the primary zinc-air battery (ZAB) with the Co-Co3O4@NAC as a cathode catalyst shows a high open circuit voltage (OCV) of 1.449 V, a specific energy density of 721 mA h/g and a maximum power density of 164 mW/cm2. The rechargeable ZAB with this catalyst displays a low voltage gap of 0.773 V at 10 mA/cm2 and stable cycling performance. This work provides a novel tactic to design elaborate high-efficient and promising bifunctional catalysts with non-noble metal atom and metal oxide for metal-air batteries.

Two-step route for manufacturing the bio-mesopores structure functional composites by mushroom-derived carbon/Co3O4 for lithium-ion batteries

Biomass materials have attracted much attention in the functional composites, due to the bio-mesopores structure, recyclability and electrochemical properties. Herein, a two-step route for manufacturing the mushroom-derived carbon/Co3O4 functional composite (MC/Co3O4-FC) has been developed, based on carbonizing mushroom and ultrasonic coating Co3O4. The experimental results indicate that MC/Co3O4-FC has bio-mesopores structure and the sizes of pores are between 3.0 nm and 6.5 nm. In addition, the specific surface area of MC/Co3O4-FC is 122.4 m2 g−1. As an anode material, the MC/Co3O4-FC shows a reversible capacity of 528.1 mAh g−1 at a current density of 100 mA g−1 after 200 cycles, about twice as well as MC (~262 mAh g−1). Even at a high current density of 2000 mA g−1, the discharge capacity of MC/Co3O4-FC also can reach to 260 mAh g−1. The good electrochemical performances can be imputed to the bio-mesopores structure and synergistic effect between MC and Co3O4 particles. Furthermore, a solid electrolyte of polymer (instead of the liquid electrolyte) has been also prepared to improve the safety performance and electrochemical performances (298 mAh g−1).