One dimensionally spinel NiCo2O4 nanowire arrays: facile synthesis, water oxidation, and magnetic properties

Su, Yu‐Zhi; Xu, Qizhi; Chen, Gao‐Feng; Cheng, Hui; Li, Nan; Liu, Zhao‐Qing

doi:10.1016/j.electacta.2015.06.092

Cited by 141 publications

(62 citation statements)

References 41 publications

(48 reference statements)

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“…1) and previously reported data [8,23,26]. There appears to be a small amount of contamination from Ni(OH) 2 and Co 3 O 4 in the templated materials.…”

Section: Resultssupporting

confidence: 62%

Polymer templated nickel cobaltate for energy storage

Albohani

Minakshi

Laird

2017

Renew. Energy Environ. Sustain.

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Abstract. In order to take advantage of the increasing sophistication of technology for harnessing renewable energy resources, serious attention must be paid to how to store and re-access this energy. Electrochemical storage, in the guise of batteries, supercapacitors and pseudocapacitors, has attracted much attention as a viable option for enhanced energy storage applications. But in order for these technologies to be implemented successfully we need to find materials that perform better and are relatively easy to synthesise. Bimetallic transition metal oxides are materials that are readily synthesised and may be multifunctional, i.e. have a role at the electrochemical atomic level as well as the device level. In order for these materials to work efficiently in new generation systems based on sodium and lithium they also need to be mesoporous. This can be achieved by trying to find synthetic techniques that produce specific, highly regulated nanostructures or by adding a 'templating' agent during the bulk synthesis step. We have investigated the simple hydrothermal preparation of a number of nickel cobaltate (NiCo 2 O 4 ) materials using polymer templates, eggshell membrane (ESM) and poly methyl methacrylate (PMMA), as potential electrode materials for supercapacitors. The ESM was expected to act as a fibrous, random polymeric template while the PMMA should produce a much more ordered material. Electrochemical testing showed that the different templates have led to changes in material morphology and these have resulted in a difference in electrochemical properties. Templated materials increased specific capacitance compared to non-templated and the choice of template could influence the capacitance by as much as 30%.

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“…1) and previously reported data [8,23,26]. There appears to be a small amount of contamination from Ni(OH) 2 and Co 3 O 4 in the templated materials.…”

Section: Resultssupporting

confidence: 62%

Polymer templated nickel cobaltate for energy storage

Albohani

Minakshi

Laird

2017

Renew. Energy Environ. Sustain.

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“…An oxidation current peak at ca . 1.305 V vs. RHE was observed for the MWNT-PyPBI-Ni x Co 3− x O 4 , which can be ascribed to the Ni 3+ /Ni 2+ redox couple of NiCo 2 O 4 35. We consider that the pristine MWNTs provide efficient electron conducting paths for the Ni x Co 3− x O y nanoparticles, which promotes the electron transfer process and thus improve the OER activity of the MWNT-PyPBI-Ni x Co 3− x O 4 .…”

mentioning

confidence: 90%

“…For the MWNT-PyPBI-Ni(OH) 2 , the Ni 2p peaks shifted to a higher band energy compared to those of the MWNT-PyPBI-Ni x Co 3− x O 4 and can be attributed to Ni(OH) 2 34. For MWNT-PyPBI-Co 3 O 4 , the coexistence of Co 2+ and Co 3+ was recognized35. The above results suggested that we have succeeded in coating the PyPBI-wrapped MWNTs with uniform Ni/Co spinel oxide nanoparticles to provide the MWNT-PyPBI-Ni x Co 3− x O 4 .…”

mentioning

confidence: 90%

Decorating unoxidized-carbon nanotubes with homogeneous Ni-Co spinel nanocrystals show superior performance for oxygen evolution/reduction reactions

Yang

Fujigaya

Nakashima

2017

Sci Rep

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We present a new concept for homogeneous spinel nanocrystal-coating on high crystalline pristine-carbon nanotubes (CNTs) for efficient and durable oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Oxidized CNTs have widely been used to functionalize with metal or metal oxides since the defect sites act as anchoring for metal oxide binding. However, such defects on the tubes cause the decrease in electrical conductivity and stability, leading to lower catalyst performance. In the present study, at first, pristine multi-walled carbon nanotubes (MWNTs) were wrapped by pyridine-based polybenzimidazole (PyPBI) to which uniform NixCo3−xO4 nanocrystals were homogeneously deposited by the solvothermal method without damaging the MWNTs, in which PyPBI acted as efficient anchoring sites for the deposition of spinel oxide nanocrystals with ~5 nm size. The obtained catalyst (MWNT-PyPBI-NixCo3−xO4) outperformed most state-of-the-art non-precious metal-based bifunctional catalysts; namely, for OER, the potential at 10 mA cm−2 and Tafel slope in 1 M KOH solution were 1.54 V vs. RHE and 42 mV dec−1, respectively. For ORR, the onset and half-wave potentials are 0.918 V and 0.811 V vs. RHE, respectively. Moreover, the MWNT-PyPBI-NixCo3−xO4 demonstrates an excellent durability for both ORR and OER.

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“…The O3 component at 531.4 eV is essentially the signature of water bound to the surface of the sample [49,54]. Figures S4c and S5c clearly show the Co spin-orbit doublets as well as the shakeup satellite features of Co 2+ and Co 3+ ions in the samples [24,26]. Similarly, Ni 2p spectra in Figs.…”

Section: Resultsmentioning

confidence: 71%

“…Mixed valence of transition metal oxides with spinel structure such as NiCo 2 O 4 [22][23][24][25][26][27][28] CoMn 2 O 4 [29,30], CoFe 2 O 4 [31], CuCo 2 O 4 [32], and ZnCo 2 O 4 [33,34] is another class of materials which exhibit good OER activity because of multiple oxidation states, better electrical conductivity, and stability. The electrocatalytic activity of NiCo 2 O 4 has been found to be superior compared to other binary metal oxides due to its high electrical conductivity and rich redox reactions which originate from both nickel and cobalt cations [22][23][24][25]35].…”

Section: Introductionmentioning

confidence: 99%

NiCo2O4/rGO hybrid nanostructures for efficient electrocatalytic oxygen evolution

Umeshbabu

Rajeshkhanna

Justin

et al. 2016

J Solid State Electrochem

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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.

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One dimensionally spinel NiCo2O4 nanowire arrays: facile synthesis, water oxidation, and magnetic properties

Cited by 141 publications

References 41 publications

Polymer templated nickel cobaltate for energy storage

Polymer templated nickel cobaltate for energy storage

Decorating unoxidized-carbon nanotubes with homogeneous Ni-Co spinel nanocrystals show superior performance for oxygen evolution/reduction reactions

NiCo2O4/rGO hybrid nanostructures for efficient electrocatalytic oxygen evolution

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