Nickel Cobalt Oxide Research Articles

Utilization of spray pyrolyzed porous nickel cobaltite electrode as an advanced material for NiCo2O4@Graphite asymmetric supercapacitor device

Nickel-based probe ingredients are vastly promoted in energy storage devices due to their simply variable structure, greater electrochemical movement and nominal noisomeness. In the existing manuscript, we did a comparative study of spray pyrolyzed nickel oxide and nickel cobaltite thin film electrodes and their asymmetric supercapacitor devices for supercapacitor applications. In a three-electrodes arrangement, pristine nickel oxide shows a maximum specific capacitance of 397.10 Fg−1 at 0.002 V scan rate with 86.40 % retention after 5000 cycles. The same electrode shows the values of energy density and power density 45.16 Whkg−1 and 05 Wkg−1 respectively. Nickel cobaltite (NiCo2O4) electrode exhibits the highest value of specific capacitance is 676.82 Fg−1 with 89.23 % retention after 5000 cycles and the values of energy and power densities are 1123.41 Whkg−1 and 5.76 Wkg−1 respectively. The fabricated NiCo2O4@graphite asymmetric device shows a specific capacitance (according to CV analysis) of 495.10 Fg−1. According to the GCD analysis, the NiCo2O4@Graphite device exhibits a specific capacitance of 675.72 Fg−1 and the energy and power densities are 3249.6 Whkg−1 and 10 Wkg−1 respectively. The outcomes show that nickel–cobalt oxide materials play an important role in the field of energy storage.

Synergistic electrochemical sensing of 2,4-dinitrotoluene via bimetallic nickel-cobalt oxide nanoparticles

This study presents a comprehensive investigation into the synthesis, characterization, and application of an exceptionally sensitive electrochemical sensor designed for the ultrasensitive detection of 2,4-dinitrotoluene (DNT), a notorious explosive compound. The sensor employs bimetallic nickel-cobalt oxide (NiCo2O4) nanoparticles, synthesized through a facile hydrothermal method. Extensive analytical techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS), were employed to validate the crystallinity and purity of the NiCo2O4 nanoparticles. These nanoparticles, possessing remarkable properties, form the core of our electrochemical sensor, enabling it to offer heightened sensitivity and selectivity even under ambient conditions. Most notably, this sensor boasts an impressively low limit of detection (LOD) of 18 nM, coupled with a broad linear detection range (LDR) spanning from 10 nM to 100 nM. The sensor exhibits robust sensitivity, excellent selectivity, and an outstandingly low detection threshold, collectively demonstrating its potential for precise and accurate detection of DNT. This research underscores the significant potential of bimetallic oxide nanoparticles, specifically NiCo2O4, in the precise quantification of nitro-aromatic analytes. This study opens up promising avenues for assessing hazardous compounds in complex environmental matrices, thereby contributing to the advancement of electrochemical sensing. Additionally, this novel sensing platform holds substantial promise for enhancing security measures and environmental monitoring through its improved sensitivity and selectivity in the detection of explosives.

Structural property, temperature-resistance characteristics and infrared detection performance of manganese cobalt nickel oxide films deposited by sputtering under different oxygen concentrations

Structural property, temperature-resistance characteristics and infrared detection performance of manganese cobalt nickel oxide films deposited by sputtering under different oxygen concentrations

Nickel–cobalt oxide nanoparticles as superior electrocatalysts for enhanced coupling hydrogen evolution and selective ethanol oxidation reaction

The selective oxidation of organic small molecules not only promotes cathodic hydrogen production, but also acts as an alternative reaction to the anodic oxygen evolution reaction of electrolytic water, producing value-added products at the anode.

In-situ hydrothermal synthesis of a novel morphology daisy shape nickel cobalt oxide films for high performance supercapattery

NiCo2O4 is widely used in traditional battery and supercapattery due to its extremely high capacitance value. Herein, the in-situ hydrothermal method has been optimized in order to utilize its own charge storage capacity. NiCo2O4 nanosheet thin films with four different morphologies (wrap, neuron, daisy, and tablet shape) are synthesized on Ni foam surface without mechanical stress damage. In the absence of interference from conductive agents and binders, these NiCo2O4 nanosheet thin films with different morphologies provide various conducive channels for charge transfer and more sites for redox reactions achieve better energy storage properties. Particularly, the daisy shape NiCo2O4 nanosheets have the highest capacity (C g−1) of 972.5 (2 M KOH) at 1 A g−1 comparing to others. Furthermore, after subjecting it to 1800 cycles of cyclic stability testing at 40 A g−1, its capacity (C g−1) remarkably increased to 1433.5. In addition, using the daisy shape NiCo2O4 nanosheets thin film and activated carbon, a supercapattery is assembled. The results exhibit that it has an impressive performance of 39.8 W h kg−1 at 750 W kg−1 comparing to other works, which demonstrates that our in-situ hydrothermal synthesized daisy shape NiCo2O4 nanosheet has significant potential in the field of energy storage.

Construction of hierarchical ZnO-NiCo2O4-NiCo2O4 core-shell microstructure with efficient microwave absorption

Core-shell structural design is an attractive strategy to achieve high-performance microwave absorbers. Nevertheless, it still remains a problem to simultaneously obtain superior microwave dissipation and impedance matching for microwave absorption (MA) materials. In this work, ZnO-NiCo2O4-NiCo2O4 (ZNN) core–shell microstructure is designed and fabricated by covering NiCo2O4 nanosheets on the surface of ZnO nanorod and next growth of NiCo2O4 nanoparticles. With the synergies from the NiCo2O4 nanosheets improving the microwave attenuation capability and the NiCo2O4 nanoparticles increasing the impedance matching, ZNN possesses efficient MA performance: the strongest reflection loss is −59.93 dB at the corresponding thickness of 2.6 mm, and the maximum absorption bandwidth is 7.04 GHz at 2.4 mm, which covers the entire Ku-band. RCS simulation also indicates that ZNN has outstanding MA performance. Moreover, this study proposes a point for the utilization of nickel–cobalt oxides in MA materials, and offers a reference for the design of core–shell structural absorbers.

Digital Composition Control of Cobalt Nickel Oxides by ALD for the Oxygen Evolution Reaction

Anion exchange membrane water electrolysis is a potentially low-cost and sustainable technology for renewable-energy driven hydrogen production. Realisation of its full potential relies on the development of cost-effective, earth-abundant OER electrocatalysts alternatives to the state-of-the art noble metal oxides1. Ternary transition metal oxides, such as cobalt nickel oxides, are promising candidates due to their excellent alkali resistance in combination with remarkable catalytic activities. The latter relate to their tuneable oxidation states and variation in coordination of their metal centres. These correlations can be properly investigated when precise control over the layer chemical composition is attained. Atomic layer deposition (ALD) is widely acknowledged to deliver control over film uniformity, thickness and conformality, as well as film chemical composition due to the self-limiting nature of its surface reactions.In this study, an ALD supercycle process based on cobalt cyclopentadienyl (CoCp2) and nickel methylcyclopentadienyl (Ni(MeCp)2) precursors and an oxygen plasma co-reactant has been developed2 to investigate the influence of chemical composition and crystallographic properties of cobalt nickel oxide thin films on their electrocatalytic OER performance. Deposition of ~20 nm binary nickel oxide and cobalt oxide results in the growth of polycrystalline films of the rock-salt and spinel phase, respectively. Ternary cobalt nickel oxide films with various ratios can be deposited uniformly, as indicated by energy dispersive x-ray spectroscopy mapping. The mixed oxides display a transition from the +2 oxidation state-based pure rock-salt phase (<25 at.% Co) to the spinel phase consisting of mixed +2/+3 oxidation states (>75% at.% Co) upon increasing Co at.% as verified by electron diffraction (figure a) and x-ray photoelectron spectroscopy (XPS). XPS furthermore reveals a linear increase in the Ni3+-to-Ni2+ ratio with increasing Co at.%, which indicates that an inverse spinel structure is formed. The formation of a Ni3+-rich inverse spinel cobalt nickel oxide between 55 and 75 at.% Co facilitates the formation of a semi-metallic state (102 S/cm) as opposed to the poorly conductive binary oxides (10-3 S/cm and 10-2 S/cm for NiO and Co3O4, respectively).Cyclic voltammetry (CV) measurements in 1M KOH, reveal chemical composition dependent activation behaviour (figure b). Continuous activation behaviour is observed for rock-salt phase films, whilst increment of the Co at.% results in reduced film activation until virtually no activation of the spinel phase films is observed. The activation of the nickel-rich film is accompanied by irreversible redox changes from the +2 to +3 oxidation state as indicated by the integrated non-catalytic wave. Post CV XPS analysis confirms the transition from Co2+ and Ni2+ oxidation states to Co3+ and Ni3+. The formation of an (oxy)hydroxide state is observed for the rock-salt dominated films, whilst oxidation states characteristic of a spinel- like oxide structure are observed for the cobalt-rich films. No changes in the transition metal ratios are observed after activation. Scanning electron microscopy images furthermore reveal that the transformation of the Ni-rich films is accompanied by surface restructuring. These results indicate that initial composition can significantly influence the electrocatalytic performance of ternary oxides and therefore highlight the importance of techniques such as atomic layer deposition to study their complex behaviour. 1Xu et al., Energy Chem., 4 (2022) 100087 2van Limpt et al., J. Vac. Sci. Technol. A, 41 (2023) 032407 This work has been carried out within the SCALE project (NWA.1237.18.001) funded jointly by the Netherlands Organization for Scientific Research. Authors would like to thank the co-founders of the project ISPT, Syngaschem, VecoPrecision and Vsparticle and international partners Toyota Motor Europe and FORTH institute. Figure:(a) ALD deposited cobalt nickel oxide film show a transition from the +2 oxidation state-based rock-salt phase (NiO) to the spinel structure consisting of mixed +2/+3 oxidation states (Co3O4) upon tuning the chemical composition as identified by electron diffraction. (b) This significantly affects the OER-electrocatalytic performance and activation of the films as represented by the current density at 1.8V vs RHE over 500 CV cycles in 1M KOH. Data labels indicate cobalt concentration as at.% Co/(at.% Co+ at.% Ni). Figure 1

Investigation of NiCoOx catalysts for anion exchange membrane water electrolysis: Performance, durability, and efficiency analysis

Anion exchange membrane (AEM) water electrolysis is a promising method for hydrogen production using inexpensive metal oxide catalysts. This study investigates the catalytic activity and performance of nickel cobalt oxide (NiCoOx) catalysts in AEM water electrolysis for hydrogen production. The catalysts were synthesized with varying ratios of Ni to Co. The NiCoOx catalysts were coated on nickel foam gas diffusion layer (GDL) at the anode. Scanning electron microscopy (SEM) analysis revealed a distinct flaky structure of the NiCoOx catalyst. X-ray diffraction (XRD) studies confirmed the presence of NiCo2O4 spinel crystal structure in the catalysts. Linear sweep voltammetry (LSV) measurements for Oxygen evolution reaction (OER) in three electrode systems showed that NiCoOx (1:3) exhibited the highest catalytic activity, with a current density of 238 mA cm−2 at 1.8 V. Tafel analysis indicated that NiCoOx (1:3) had the lowest Tafel slope, suggesting faster reaction kinetics and lower overpotential for higher current density. Chronoamperometry tests demonstrated the stability of the catalysts at various current densities, and long-term stability testing of NiCoOx (1:3) for 500 h revealed minimal voltage increase during OER, demonstrating its stability in prolonged operation. NiCoOx (1:3) displayed the highest activity among the catalysts at different temperatures, with current densities reaching 1700 mA cm−2 at 2.2 V and 70 °C for single-cell electrolysis. The Nyquist plots and equivalent circuit analysis reveal that the NiCoOx (1:3) catalyst exhibits lower activation resistance and higher efficiency in oxygen evolution reaction compared to other catalyst compositions. Temperature-dependent measurements demonstrate decreased resistances (ohmic, activation, and membrane) with increasing temperature, indicating improved reaction kinetics and ion conductivity. Long-term durability tests reveal the stable operation of the catalyst, while short-term tests confirm its effectiveness at higher current densities for single-cell electrolyzer operation. These findings highlight the importance of electrochemical Impedance Spectroscopy (EIS) and equivalent circuit fitting in optimizing AEM water electrolysis performance, aiding the development of efficient and durable electrolyzers for hydrogen production.

Development of vertically aligned NixCo3-xO4 nanowires for supercapacitors

Nickel-cobalt oxide is a type of transition metal oxide which is extensively accredited as an outstanding electrode material for application in supercapacitors. It outperforms single components in terms of superior specific capacitance and incredible rate capability. In this perspective, porous NixCo3-xO4 nanowires have been effectively engineered using a hydrothermal apprroach followed by calcination. The resulting porous NixCo3-xO4 nanowire electrodes display significant properties. They achieve a better specific capacitance (1191.4 F/g) at 1 A/g with superior cycling stability. Interestingly, the NF does not only act as 3Dmacroporousconductive current collector but also as a source of Ni for the formation of NixCo3-xO4 nanowire. These exceptional properties position porous NixCo3-xO4 nanowires as a highly capable prospect for energy storage applications.

Electrochemical Performance of Nanosheet-like Structured Nickel-Cobalt Oxide Thin Films

Electrochemical Performance of Nanosheet-like Structured Nickel-Cobalt Oxide Thin Films

Electrochemical Detection of Metol through the Cobalt Nickel Oxide Nanosheets Incorporated with MCM-41 Nanospheres Composites Modified Glassy Carbon Electrode

In this study, contaminations of metol (or Elon) in environmental water and industrial wastewater are the major causes of toxicity, which is very harmful to human health and other living things. Hence the determination of metol in high demand is more important. Further, the Mobil Composition of Matter (MCM-41) mesoporous silica nanoparticles incorporated with cobalt nickel oxide (CoNiO2) complex to form MCM-41/CoNiO2 composite modifying the glassy carbon electrode (GCE) used for metol detection. The MCM-41/CoNiO2 composite coated on the GCE surface exhibited fast electron transfer kinetics, improved conductivity, a large surface area, active stability, and improved catalytic efficiency. The structural morphology of the MCM-41/CoNiO2 composite was investigated using several spectroscopic and microscopic techniques. Here, the MCM-41/CoNiO2 composite was verified using different characterization studies such as Field Emission Scanning Electron Microscopy, Transmission Electron Microscopy, Energy Dispersive X-ray Analysis, X-ray Diffraction Analysis, and X-ray Photoelectron Spectroscopy. Additionally, the electrochemical investigations have included Electrochemical Impedance Spectroscopy, Cyclic Voltammetry, and Differential Pulse Voltammetry studies. The GCE/MCM-41/CoNiO2 electrode shows a low detection limit of 10 nM and the LOQ value is 0.1 μM with a broad linear response range of 0.1–750 μM, and greater sensitivity of 0.411 μA μM−1 cm−2 under optimal voltammetry.

Gamma-irradiated fluorophosphate glasses doped with various transition metals: A spectroscopic study

The 20NaF–60P2O5–20Na2O fluorophosphate glass systems doped with 3 wt% of CoO and NiO were manufactured using traditional melting techniques. Optical parameters were investigated for the studied composites before and after irradiation by 20 kGy of gamma rays. For the studied composites, the presence of defects within the glass network can explain the decrease of the Urbach energy (Eu) due to gamma irradiation or the increase in it due to the addition of the transition metals (nickel oxide and cobalt oxide) to the base composite. After gamma irradiation, a red shift was seen in the spectrum of the dissipation factor (tan δ). According to the calculated values of volume energy loss function (VELF), and surface energy loss function (SELF), the energy lost at the surface of the composites under investigation is larger than the energy lost within the composites' constituent materials. All investigated composites demonstrated an insulating property by obtaining the values of the covalency parameter (M) less than unity. All of the nonlinear optical parameters were increased after irradiation of the studied composites, whereas the highest values were recorded for the irradiated composite doped by CoO. Following the intrinsic and extrinsic defects produced by the former oxide itself and by added modified oxide dopants inside the glassy network was important to explain changes inside the network by ESR spectra for prepared fluorophosphate composites. Moreover; defects induced inside the glass network by 20 kGy of γ-ray have been followed to continue the ongoing study of the nature of the prepared glassy network.

Carbon-supported Pd/NiO-CoOx nanoparticles for highly selective and stable 1-nitroanthraquinone hydrogenation

1-aminoanthraquinone has numerous applications in chemical industry, for example, it is an important intermediate for producing anthraquinone dyes. In this work, Pd/NiO/C, Pd/CoOx/C, and Pd/NiO-CoOx/C (C-carbon black) are prepared by room-temperature hydrazine hydrate and replacement reduction methods. All as-prepared catalysts have been characterized by XRD, SEM, TEM, HRTEM, XPS, STEM-EDX elemental mapping and line-scanning et al., The Pd-related species are highly dispersed on the nickel, cobalt or nickel-cobalt oxide nanoparticles (NPs), the interaction of Pd–NiO (or CoOx, NiO-CoOx) is present. Pd/NiO-CoOx/C provides 99.2 % conversion of 1-nitroanthraquinone and 91.0 % selectivity to 1-aminoanthraquinone for 1-nitroanthraquinone hydrogenation under the following reaction conditions: H2 pressure-3.0 MPa, 60 °C, 4 h. The catalytic behaviors of Pd/NiO-CoOx/C for 1-nitroanthraquinone hydrogenation are much better than Pd/NiO/C and Pd/CoOx/C mainly due to the interaction of Pd–NiO-CoOx, synergy effect of Pd and NiO-CoOx, and high Pd dispersion.

Nickel-cobalt phosphide nanowires as precatalysts for surface reconstruction to prepare durable and efficient OER catalysts

The investigation of transition metal phosphides (TMPs) as efficient electrocatalysts for water splitting has garnered significant attention in academic research. Nevertheless, limited research has been conducted on the alteration of the structural and morphological properties of TMPs resulting from the unavoidable surface reconstruction during the oxygen evolution reaction (OER). This study introduces a newly developed catalyst, namely nickel–cobalt phosphide nanowires (NiCoP), which facilitates the in-situ growth of nickel–cobalt oxide (NiCo2O4) through surface reconstruction during anodic potential cycling in alkaline electrolytes. The catalyst's extensive modification can be observed through ex-situ characterization techniques. The catalyst undergoes a significant transformation that ultimately yields a phosphide scaffold, leading to the formation of a spinel oxide surface. This transformation enhances the catalytic environment for the OER, making it highly efficient and potent. The transformed catalyst demonstrates comparable catalytic performance to the precious RuO2 catalyst across various current densities. Importantly, it exhibits remarkable long-term stability, as demonstrated by its ability to sustain continuous operation for 72 h at a current density of 50 mA while maintaining stable catalytic performance.

Preparation and theoretical analysis of NiCo2O4: xS series materials for high-performance supercapacitors

Nickel cobalt oxide and sulfide electrode materials with various nanostructures were synthesized via a facile hydrothermal method. The structural, morphological, electrochemical, and electronic properties of the electrode materials were studied to evaluate the effect of S addition into NiCo2O4. The results indicated that S atoms can influence the lattice structure and morphology, and appear to improve the electrochemical performance of the material. Excellent specific capacitance and cycling stability were found in the samples. The NiCo2S4 sample exhibited the highest specific capacitance of 1302 F/g at a current density of 1 A/g and a capacity retention of 92.4% after 5000 charge–discharge cycles. First-principles calculations were performed to provide more insight into the mechanism of improved electrochemical performance when S atoms were added to NiCo2O4 and demonstrate their potential as excellent electrode materials. In the NiCo2O4:xS series materials, the addition of S effectively manipulates the surface morphology and interfacial charge states of the materials to achieve superior electrochemical performance.

Facile hydrothermal synthesis and fabrication of nickel cobalt oxide as an advanced electrode for electrochemical capacitors

The surface chemistry and decent morphology of electrode materials are highly desirable for high-performance energy storage/conversion devices. Bimetallic oxides especially nickel cobalt oxide (NCO) have gained substantial attention in energy storage/conversion devices owing to their exclusive electronic properties. Herein, flower-like nickel cobalt oxide (NiCo2O4) was prepared by a facile hydrothermal method for different reaction times. The properties of obtained samples were characterized through X-ray diffraction (XRD), EDS, field-emision scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). The cyclic voltammogram (CV), Galvanostatic changing discharging (GCD), and electrochemical impedance spectroscopy (EIS) were employed for the evaluation of the electrochemical performances of the resultant product. The flower-like NiCo2O4 electrode exhibits high areal capacity (392 mF cm−2 at 0.5 mA cm−2) and the electrode shows an energy density of about 9.1 µWh cm−2 at power density 102 µW cm−2. The excellent electrochemical performance of the fabricated supercapacitor offers good areal capacitance and energy density that exceeds several carbon-based materials.

Three-dimensional spherical NiCoOX@NiCo layered double hydroxides nanosheets for high-performance all-solid-state supercapacitors

The low conductivity of cobalt-based oxides greatly limits its application in supercapacitors (SCs). Recently, construction of heterogeneous structural materials has emerged as an effective way to solve this problem. Herein, nickel‑cobalt oxide @ nickel‑cobalt layered double hydroxides (NiCoOX@NiCo LDH) heterostructure is synthesized by an electrodeposition-annealing-electrodeposition step, in which the inner nickel‑cobalt oxide (NiCoOX) layer is firstly deposited on the carbon cloth with a subsequent annealing process, and the outer nickel‑cobalt layered double hydroxides (NiCo LDH) layer is electrodeposited on the prepared NiCoOX layer. Benefiting from the multi-channel structure and extensive specific surface area produced by the heterogeneous structure material, as same as its synergistic effect, at 1 A g−1, NiCoOX@NiCo LDH exhibits an extremely advanced specific capacitance (2451 F g−1). It is much better than pure NiCoOX and pure NiCo LDH. Meanwhile, its specific capacitance retention rate still keeps 62.8 % even at 20 A g−1, indicating its excellent rate property. Furthermore, the assembled all-solid-state asymmetric SCs with NiCoOX@NiCo LDH//Active carbon (AC) exhibits a high energy density of 34.9 Wh kg−1 when the power density is 800 W kg−1. Meanwhile, it has a high capacitance retention of 81.79 % (10 A g−1) after 10,000 cycles, which indicates a remarkable cycle life.

Fuel dependent combustion synthesis and electrochemical characteristics of nickel cobalt oxide nanoparticles

The electrochemical activity of the nickel–cobalt oxide (NiCoO2) nanoparticles (NPs) is strongly dependent upon its morphology, composition, phase, and the presence of functional groups and metal ions (Ni and Co) on the surface of NiCoO2 NPs. These characteristics can be tailored by the choice of synthesis method and reaction parameters adopted for its preparation. In this work, we have synthesized two different samples of NiCoO2 by solution combustion method employing glucose and thioacetamide as fuels. The electrocatalyst synthesized using glucose as fuel (S1) exhibited enhanced reactivity as compared to the sample prepared using thioacetamide (S2) as fuel. The reduction of the glucose during the preparation of sample S1 resulted in the enhancement in electrochemical surface area (ECSA). The high ECSA results in a higher rate of charge storage reaction. The above analysis is further supported using electrochemical impedance spectroscopy (EIS) data. The high pseudo-capacitance and low charge transfer resistance of sample S1 are attributed to the high ECSA and optimized surface energy. Thus, the fuel variation in the nanoparticle fabrication plays a critical role in the enhancement of the supercapacitor activity of the electrocatalyst.

Enhanced Performance of Nickel–Cobalt Oxides as Selective Coatings for Flat-Plate Solar Thermal Collector Applications

Solar thermal collectors represent a practical option to capture energy from the sun, providing low-cost domestic and industrial heating and decreasing the dependency on fossil fuels. Spinel-type metal oxides show interesting physicochemical properties and so can be used as active materials for converting solar energy to electrical, chemical, and heat energy. We report the synthesis and characterization of nickel–cobalt mixed metal oxides used as an active phase in selective paints for solar absorber coatings applied to a domestic flat collector. The nickel–cobalt mixed oxides crystallized in the cubic phase related to the spinel structure, exhibiting good thermal stability and reproducibility. These mixed oxides presented oxidation states (2+ and 3+) for both nickel and cobalt. The coatings fabricated from the selective paints based on nickel–cobalt mixed oxides showed a solar absorptance value of 94%, while for the commercial paint Solkote®, the value was 93%. A representative coating based on the NiCo2O4 composition was evaluated for the first time in a domestic-type flat solar collector for water heating under real operating conditions, achieving an outstanding performance that competes with that of commercial collectors. The potential application of nickel–cobalt mixed oxides in solar collectors opens up new opportunities for future innovations and developments in functional absorber coatings.

Nickel-Cobalt oxides coated on polypyrrole nanotubes as bifunctional electrode catalyst for enhancing the performance of the microbial fuel cells

The surface modification of electrodes is a vital technique for improving the power output of microbial fuel cells (MFCs). In this study, a single bifunctional catalyst material, Nickel (Ni)-cobalt (Co) oxides coated on polypyrrole nanotubes (PNT) (NiCo2O4@PNT), is prepare and used as the electrode catalyst material for a single chambered MFC. The catalyst show excellent oxygen reduction reaction (ORR) activity and work as a good electron acceptor at the anode. The electrocatalytic activity of the prepared catalyst is inspected by cyclic voltammetry (CV), which showed the highest reduction peak for NiCo2O4@PNT at 0.0621 mA. Four different catalysts have been prepare in this study NiCo2O4@PNT, NiO@PNT, CoO@PNT and PNT. The maximum power density of NiCo2O4@PNT is 427.52 mW/m2 (anode) and 916.12 mW/m2 (cathode), which is significantly higher than those of the other catalysts. These results suggest that NiCo2O4@PNT is a promising bifunctional catalyst for MFCs.