Magnetic, optical and electrocatalytic properties of urchin and sheaf-like NiCo2O4 nanostructures

Mesoporous NiCo2O4 materials with different 3D structures, including flower‐like hierarchical structures (NCO‐flower‐like HSs), nanoflake@nanoneedle‐like multiple hierarchical structures (NCO‐MHS) and urchin‐like hierarchical structures (NCO‐urchin‐like HSs), were prepared by using a facile, one‐step, NH4F‐induced hydrothermal method followed by thermal annealing. The physicochemical characterization of the as‐prepared materials was investigated by means of X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and X‐ray photoelectron spectroscopy. The performance of the synthesized NiCo2O4 material as supercapacitor electrode materials was measured and the results demonstrate that the NCO‐MHSs and NCO‐urchin‐like HSs exhibit high specific capacitance values of 640 and 655 F ⋅ g−1 at a current density of 1 A ⋅ g−1, whereas the capacitance retention is 99.6 and 95 %, respectively, after 1000 cycles at a current density of 5 A ⋅ g−1. The electrocatalytic performance of synthetized NiCo2O4 for methanol electro‐oxidation was evaluated in 1 M KOH electrolyte. The NCO‐MHSs and NCO‐urchin‐like HSs deliver an electro‐oxidation current density of 51 and 48.5 A ⋅ g−1, respectively, at 0.65 V with excellent stability. The results indicate that the hierarchical structure of NiCo2O4 offers a promising electrode material for supercapacitors and methanol electro‐oxidation.

show abstract

“…The redox reactions in the alkaline electrolyte are based on the following equations [Eqs. ]:

true NiCo_{2} normalO_{4} + OH^{-} + normalH_{2} normalO \leftrightarrow NiOOH + 2 CoOOH + normale^{-}

true CoOOH + OH^{-} \leftrightarrow CoO_{2} + normalH_{2} normalO + normale^{-}

…”

Section: Resultsmentioning

confidence: 99%

“…This may be due to NiCo 2 O 4 is a mixed valence oxide. These redox couples can act as electroactive center for methanol electro‐oxidation reaction . Figure (a–c) depicted the CV curves of above synthesized electrocatalysts tested with 0.5 M CH 3 OH in 1 M KOH solution at a scan rate of 10 mV s −1 .…”

Section: Resultsmentioning

confidence: 99%

Mesoporous NiCo₂O₄ Micro/nanospheres with Hierarchical Structures for Supercapacitors and Methanol Electro–oxidation

Zhang

Ren

et al. 2017

ChemElectroChem

View full text Add to dashboard Cite

show abstract

“…The Raman spectra of NiCo 2 O 4 /rGO composites clearly show the F 2g , E g , F 2g , and A 1g phonon modes of NiCo 2 O 4 at around 185, 460, 508, and 651 cm −1 originating from the vibrations of Co-O and Ni-O bonds [53]. The FTIR spectra of GO and NiCo 2 O 4 /rGO samples are shown in Fig.…”

Section: Resultsmentioning

confidence: 92%

NiCo2O4/rGO hybrid nanostructures for efficient electrocatalytic oxygen evolution

Umeshbabu

Rajeshkhanna

Justin

et al. 2016

J Solid State Electrochem

Self Cite

View full text Add to dashboard Cite

We report the synthesis of NiCo 2 O 4 /reduced graphene oxide (NiCo 2 O 4 /rGO) hybrid hierarchical structures with unique nanonet and microsphere morphologies by organic polar solvent-assisted solvothermal method. The electrocatalytic oxygen evolution reaction (OER) activity of these materials is studied by cyclic voltammetry, linear sweep voltammetry and chronoamperometry methods in O 2 -saturated 0.1 M KOH solution. The NiCo 2 O 4 /rGO hybrid nanocomposite materials are found to be highly active electrocatalysts for OER at lower overpotentials. The nanonet and microspherelike NiCo 2 O 4 /rGO catalysts require overpotentials of 0.450 and 0.530 V at a current density of 10 mA cm −2 , and their corresponding Tafel slopes are 53 and 62 mV dec −1 , which are much lower than values reported for non-precious electrocatalysts. Further, both NiCo 2 O 4 /rGO catalysts show good catalytic stability with current retention more than 92 % over long period of 15,000 s determined by chronoampirometry and at the end of 1000th cycle determined by linear sweep voltammetry. The enhanced OER activity of nanostructured NiCo 2 O 4 /rGO hybrid catalysts is attributed to synergistic interaction between rGO and NiCo 2 O 4 , which seems to be essential for maintaining the large contact area at the electrode-electrolyte interface, better mass, and charge transport and to minimize the aggregation of NiCo 2 O 4 nanoparticles.

show abstract

“…21 Cobalt oxide similar to other spinel crystal (cubic closed packing) materials offered the compositional diversity as it can accommodate other transition metal cations (based upon ionic radii) 22−23 without deformation of the lattice and causing dislocation in grain structure. 24 Dispersion of electrons within cations of two sub lattices (tetrahedral and octahedral) causes special features as more surface atoms are actively available for reaction sites and redox action. 25 …”

Section: Introductionmentioning

confidence: 99%

Bimetallic Oxide Nanoflowers Decorated Graphene Oxide Nanosheets as Novel Nanohybrids for 4-Nitrophenol Removal at Room Temperature

Pervaiz¹,

Tareen²,

Yang³

2017

Nano Adv

View full text Add to dashboard Cite

Technological evolution is merely based upon the design and fabrication of advanced functional materials with remarkable efficiency, sustainability and cyclability. Grain size and shape of the supported nanoparticles significantly relate the reactivity and available surface sites in the nanohybrids, whereas the interfacial integration is the core point for catalysis. Herein, we synthesized pure phase

show abstract

Magnetic, optical and electrocatalytic properties of urchin and sheaf-like NiCo2O4 nanostructures

Cited by 107 publications

References 71 publications

Mesoporous NiCo₂O₄ Micro/nanospheres with Hierarchical Structures for Supercapacitors and Methanol Electro–oxidation

Mesoporous NiCo₂O₄ Micro/nanospheres with Hierarchical Structures for Supercapacitors and Methanol Electro–oxidation

NiCo2O4/rGO hybrid nanostructures for efficient electrocatalytic oxygen evolution

Bimetallic Oxide Nanoflowers Decorated Graphene Oxide Nanosheets as Novel Nanohybrids for 4-Nitrophenol Removal at Room Temperature

Contact Info

Product

Resources

About

Magnetic, optical and electrocatalytic properties of urchin and sheaf-like NiCo2O4 nanostructures

Cited by 107 publications

References 71 publications

Mesoporous NiCo2O4 Micro/nanospheres with Hierarchical Structures for Supercapacitors and Methanol Electro–oxidation

Mesoporous NiCo2O4 Micro/nanospheres with Hierarchical Structures for Supercapacitors and Methanol Electro–oxidation

NiCo2O4/rGO hybrid nanostructures for efficient electrocatalytic oxygen evolution

Bimetallic Oxide Nanoflowers Decorated Graphene Oxide Nanosheets as Novel Nanohybrids for 4-Nitrophenol Removal at Room Temperature

Contact Info

Product

Resources

About

Mesoporous NiCo₂O₄ Micro/nanospheres with Hierarchical Structures for Supercapacitors and Methanol Electro–oxidation

Mesoporous NiCo₂O₄ Micro/nanospheres with Hierarchical Structures for Supercapacitors and Methanol Electro–oxidation