Nickel-cobalt bimetallic anode catalysts for direct urea fuel cell

Xu, Wei; Zhang, Huimin; Li, Gang; Wu, Zucheng

doi:10.1038/srep05863

Cited by 173 publications

(100 citation statements)

References 28 publications

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“…However, the oxidation potential is also relatively higher, which could result in OER. On the other hand, the electrode with pure Co oxide exhibits the lowest current density, indicating that Co oxide has limited activity for the electrochemical oxidation of urea, which is consistent with other reports (Jiang and Fan, 2014;Kaushik, et al, 2008;Vedharathinam and Botte, 2013;Xu et al, 2014;Yan et al, 2012). Increasing Co content reduces the urea oxidation overpotential and simultaneously enhances the peak current.…”

Section: Electrochemical Characterization Of Ni X Co 3 à X O 4 /3d Grsupporting

confidence: 90%

Nickel/cobalt oxide-decorated 3D graphene nanocomposite electrode for enhanced electrochemical detection of urea

Nguyen

Das

Yoon

2016

Biosensors and Bioelectronics

150

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Section: Electrochemical Characterization Of Ni X Co 3 à X O 4 /3d Grsupporting

confidence: 90%

Nickel/cobalt oxide-decorated 3D graphene nanocomposite electrode for enhanced electrochemical detection of urea

Nguyen

Das

Yoon

2016

Biosensors and Bioelectronics

150

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“…7,44 In this section, we further investigated the activities of the Ni NP/NiFe LDH and NiFe LDH on urea oxidation reaction (UOR). From Fig.…”

Section: Fig 1 (As Well Asmentioning

confidence: 99%

Ni Nanoparticles Decorated NiFe Layered Double Hydroxide as Bifunctional Electrochemical Catalyst

Gao

Long

Han

et al. 2017

J. Electrochem. Soc.

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Reducing overpotential and increasing current density remain a great challenge for promoting the application of transition metalsbased layered double hydroxides (LDHs). Herein, Ni nanoparticles (∼10 nm) decorated NiFe LDH ultrathin (thickness: ∼2 nm) nanosheets (Ni NP/NiFe LDH) were successfully synthesized which exhibited advanced electrocatalytic activity and long-term stability on both oxygen evolution reaction (OER) and urea oxidation reaction (UOR). The onset potentials for OER and UOR are 1.50 V and 1.34 V, respectively, both are lower than NiFe LDH under the same conditions. Moreover, the peak current density of UOR was 300 mA/cm 2 , which is much larger than reported precious-metal free UOR catalysts. The excellent catalytic performance of Ni NP/NiFe LDH composite for OER and UOR is proposed to result from the abundant exposed active sites, small charge transfer resistance, and the synergistic effects between NiFe LDH and anchored Ni nanoparticles. This work provides inspiring ideas and helpful guidelines in design of low-cost but highly efficient electrochemical catalysts. The global energy crisis and environmental contamination have prompted intense research into the development of sustainable energy conversion and storage systems.1-10 Water splitting and direct urea fuel cell (DUFC) as promising approaches to produce clean energy recyclable, have been widely investigated recently. Nevertheless, oxygen evolution reaction (OER: 2H 2 O === O 2 + 4H + + 4e − ) suffers from a sluggish kinetics owing to a 4e-transfer process, which is frequently an obstacle to the whole water splitting. Same as OER, urea oxidation reaction (UOR: CO(NH 2 ) 2 + H 2 O === N 2 + 3H 2 + CO 2 ) is also under a multistep proton-coupled electron transfer process, which remains to be a great challenge for DUFC. As a consequence, the sluggish kinetics of OER and UOR lead to considerable overpotential and decrease the efficiency of energy conversion and storage. To achieve efficient energy conversion, much effort has been devoted to the research for robust yet stable electrochemical catalysts with reduced overpotentials. Precious metal based catalysts have shown significant electrocatalytic properties, 11-13 but their high cost and scarcity hamper the commercialization of the technique. Therefore, developing functional nanomaterials composed of cost-effective and abundant elements are on great demand.Owing to the unique physicochemical properties (e.g. tunable metal species/ratios, and exchangeable interlayer spacings, etc.), layered double hydroxides (LDHs) [23][24][25][26][27] and among which, NiFe LDH showed the best performance.28 Nevertheless, reducing the overpotential and increasing the current density remain under intensive pursuit for promoting the application of NiFe LDH. For example, the introduction of conductive materials (graphene, carbon nanotube, etc.) into LDH systems can improve the conductivity of the catalysts 21,22 and hence further enhance their catalytic performance. Herein, we report a bifunctional catalyst ...

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“…The XRD pattern revealed that the ternary alloy deposited has a cubic crystalline structure since the peaks from the characteristic cubic planes of (111), (200), and (220) were observed at 2θ ≈ 44.0, 51.0, and 76.0, respectively, suggesting that the CuCoNi system is a solid solution [26,27]. In addition, the peaks located around 2θ ≈ (37.0, 42.0) and 55.0 are attributed to NiOx and Co(OH) 2 formation, respectively [27,28]. Figure 3 shows the CVs of (a) CNTs/GCE and (b-d) metal oxide modified CNTs/GCE in 1 M NaOH solution at a scan rate of 100 mV/s.…”

Section: Discussionmentioning

confidence: 98%

High Electrocatalytic Performance of CuCoNi@CNTs Modified Glassy Carbon Electrode towards Methanol Oxidation in Alkaline Medium

et al. 2017

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Abstract:A novel non-precious multiwalled carbon nanotubes (CNTs)-supported metal oxide electrocatalyst was developed for methanol electrooxidation in alkaline medium. The catalyst was fabricated by simultaneous electrodeposition of copper-cobalt-nickel ternary nanostructures (CuCoNi) on a glassy carbon electrode (GCE) modified with CNTs. The proposed electrode was characterized using X-ray diffraction (XRD), energy dispersive X-ray (EDX), and scanning electron microscopy (SEM). The electrochemical behavior and the electrocatalytic performance of the suggested electrode towards the oxidation of methanol were evaluated by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and chronoamperometry (CA) in alkaline medium. Several parameters were investigated, e.g., deposition time, potential scan rate, etc. Compared to Cu, Co, or Ni mono electrocatalysts, the electrode based on ternary-metals exhibited superior electrocatalytic activity and stability towards methanol electrooxidation. For instance, CuCoNi@CNTs/GCE has shown at least 2.5 times electrocatalytic activity and stability compared to the mono eletrocatalysts. Moreover, the present study found that the optimized loading level is 1500 s of simultaneous electrodeposition. At this loading level, it was found that the relation between the I p /ν 1/2 function and scan rate gives the characteristic features of a catalytic process. The enhanced activity and stability of CuCoNi@CNTs/GCE was attributed to (i) a synergism between three metal oxides coexisting in the same structure; (ii) the presence of CNTs as a support for the metal oxides, that offers high surface area for the deposited tertiary alloy and suppresses the aggregation and sintering of the metals oxide with time; as well as (iii) the increase of the conductivity of the deposited semiconducting metal oxides.

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Nickel-cobalt bimetallic anode catalysts for direct urea fuel cell

Cited by 173 publications

References 28 publications

Nickel/cobalt oxide-decorated 3D graphene nanocomposite electrode for enhanced electrochemical detection of urea

Nickel/cobalt oxide-decorated 3D graphene nanocomposite electrode for enhanced electrochemical detection of urea

Ni Nanoparticles Decorated NiFe Layered Double Hydroxide as Bifunctional Electrochemical Catalyst

High Electrocatalytic Performance of CuCoNi@CNTs Modified Glassy Carbon Electrode towards Methanol Oxidation in Alkaline Medium

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