Sol-gel-deposited cobalt and nickel oxide as an oxygen evolution catalyst in alkaline media

Schoeberl, Claudia; Manolova, Mila; Freudenberger, Renate

doi:10.1016/j.ijhydene.2015.05.046

Cited by 32 publications

(8 citation statements)

References 9 publications

(6 reference statements)

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“…In this approach, Zhao et al synthesized hollow Co 3 O 4 micro spheres by an interesting selftemplate route, and showed that a high temperature led to the agglomeration of nanoparticles, a reduction of surface area, and consequently, high OP values [17]. A similar report has been also published by Schoeberl et al for solgel derived Co 3 O 4 nanoparticles [16].…”

Section: Introductionmentioning

confidence: 79%

“…Furthermore, according to Bell and Tilley's report on cata lytic activity of Co 3 O 4 nanoparticles on Ni foam, the smallest ones demonstrated the highest activity [14]. Additionally, some researchers investigated the effect of the annealing temperature on a nanostructure's performance [16][17][18]. In this approach, Zhao et al synthesized hollow Co 3 O 4 micro spheres by an interesting selftemplate route, and showed that a high temperature led to the agglomeration of nanoparticles, a reduction of surface area, and consequently, high OP values [17].…”

Section: Introductionmentioning

confidence: 99%

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Engineered cost-effective growth of Co-based nanoflakes as a sustainable water oxidation electrocatalyst

Pourreza

Naseri

2017

J. Phys. D: Appl. Phys.

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Developing low-cost, scalable and reproducible synthesis methods for water oxidation reaction (WOR) catalysts is highly desirable and also challenging in energy, environmental and industrial applications. In this context, electrochemical deposition is known as an easy and cost-effective technique in nanomaterial growth. Herein, cobalt-based nanoflakes were grown on a flexible and commercially available steel mesh substrate by electrodeposition approach with a crystalline structure as a mixture of oxide, hydroxide and oxyhydroxide phases. For the first time, the correlation between electrodeposition parameters, time and current density, and morphological characteristics of the grown nanoflakes (density and aspect ratio based on SEM results) has been derived. According to a comprehensive study of the flakes’ electrocatalytic performance in WOR, the optimized sample fabricated with a moderate electrodeposition current density (7 mA cm−2) and duration time (2000 s) revealed the highest density (7.6 × 108 cm−2) and aspect ratio (7.1) as well as the lowest values for overpotential (OP = 324 mV) and charge transfer resistance (14 Ω). This designed array of Co-based nanoflakes also showed the lowest value of overpotential for bare cobalt-based WOR electrocatalysts reported yet. High and low values for deposition current density and/or deposition time had a negative effect on the sample surface, leaving some areas without any flakes or with incomplete and inefficient formation of nanoflakes with low densities and aspect ratios. A similar effect was observed for annealed samples in the range of 200–400 °C. Based on recorded overpotentials and extracted surface morphological parameters, a linear and logarithmic behavior in overpotential–flake density dependency was proposed for current density and time controlled systems, respectively.

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Section: Introductionmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Engineered cost-effective growth of Co-based nanoflakes as a sustainable water oxidation electrocatalyst

Pourreza

Naseri

2017

J. Phys. D: Appl. Phys.

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“…The solutions and the solegel preparation procedure are the same as described previously [11] Novel AEMs have been prepared and characterized as already published [12e15]. The most promising of these new AEMS were blends composed of a bromomethylated or a chloromethylated polymer with a polybenzimidazole (PBI) as matrix, in which the anion-exchange polymer was formed in situ by addition of a tertiary amine such as 1-methylmorpholine or a N-alkylated imidazole such as 1-methylimidazole to the solution of the two polymers which reacted with the halomethyl groups under nucleophilic substitution and quaternization, forming a quaternary ammonium (or imidazolium) group which serves as anion-exchange group with the OH À ion as counter ion.…”

Section: Methodsmentioning

confidence: 99%

“…This is due to the deficient morphology of the sample at these conditions. Higher annealing temperatures change the mechanical properties of the substrate material and lead to degradation of the electrode [11].…”

Section: Anode Electrodesmentioning

confidence: 99%

Development and testing of an anion exchange membrane electrolyser

Manolova

Schoeberl

Freudenberger

et al. 2015

International Journal of Hydrogen Energy

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“…A lot of research has been conducted into mixtures of transition elements, and in many cases it has been observed that a mixture of transition-metal oxides out-performs any of the individual metal oxides on their own. Such synergistic effects have been observed for many such mixtures, including Ni-Fe [59], Ni-Co [60], [61], Ni-Co-Fe [62], Ni-Cu [63], Cu-Fe-Mo [64], Fe-Ni-Mo [65], Mn-Cr [66], Fe-Mo [67], Cu-Co [68] and Fe-Co-W [69]. In addition similar effects have been observed in other materials, such as Ni-Co Phosphide [70], Ni-Fe Nitride [71] and Ni-Fe Selenide [72].…”

Section: Mixtures and Synergymentioning

confidence: 81%

Materials Coatings and Enhanced Characterisation for Alkaline Water-Splitting Devices

Gannon¹

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A number of material coatings were investigated, specifically for 316-grade stainlesssteel electrodes, for use with alkaline water-splitting electrolysis. The aim was to enhancelongevity, particularly with respect to the highly intermittent usage that is typical of renewableenergy generation, and to increase activity. Long-term experiments were conductedover many thousands of cycles of on-off accelerated ageing at constant current density. Theeffects of ageing were analysed using chronopotentiometry, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy, energy dispersivex-ray spectroscopy, x-ray photoelectron spectroscopy and gas chromatography. It was foundthat titanium nitride did not have high activity for the hydrogen evolution reaction (HER),and underwent rapid oxidation and destruction if used as an anode. A new version ofelectrodeposited Raney nickel was developed that demonstrated improved activity, includingan overpotential for the HER at 10mAcm-2 of just 28 mV. As a bifunctional catalystit demonstrated an overpotential at 10mAcm-2 of just 319 mV, making it the second mostactive catalyst known, and certainly the simplest to deposit. This activity was traced to theincreased electrochemical surface area of the coating, which was higher as deposited, andincreased by up to a factor of three after ageing. During surface-area measurements, anapparent anomaly was discovered between results obtained for the same electrode via EISand CV. New methods of equivalent circuit fitting to transient waveforms were developed,and the anomaly was explained by time-domain simulations of the constant-phase elementrepresentation of the double-layer capacitance. A zero-gap electrolyser was constructed inorder to investigate its performance, and it was found that woven stainless-steel mesh couldoperate as a gas-separation membrane.

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Sol-gel-deposited cobalt and nickel oxide as an oxygen evolution catalyst in alkaline media

Cited by 32 publications

References 9 publications

Engineered cost-effective growth of Co-based nanoflakes as a sustainable water oxidation electrocatalyst

Engineered cost-effective growth of Co-based nanoflakes as a sustainable water oxidation electrocatalyst

Development and testing of an anion exchange membrane electrolyser

Materials Coatings and Enhanced Characterisation for Alkaline Water-Splitting Devices

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