Effect of partial substitution of Cr on electrocatalytic properties of CoFe2O4CoFe2O4 towards O2O2-evolution in alkaline medium☆

Singh, R.N.; Singh, Narendra Kumar; Singh, Jitendra; Balaji, G.; Gajbhiye, N. S.

doi:10.1016/j.ijhydene.2005.07.003

Cited by 39 publications

(23 citation statements)

References 42 publications

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“…In addition it is known that β-NiOOH can be converted to the gamma phase by so-called overcharge at extreme anodic potentials [12] , suggesting that indeed γ-NiOOH constitutes the catalytically active centre on pure Ni under harsh oxidative conditions in an alkaline medium. This interpretation is also consistent with the outcome of polarization experiments performed with Ni metal done by Lyons et al [12] , and with the recent density functional theory calculations (DFT) by Rossmeisl et al [ 55 , 56 ] [57,58,59,60] . As a short distance phenomenon it can only occur between ions within close neighbour sphere.…”

Section: The Catalytic Active Speciessupporting

confidence: 92%

Stainless steel made to rust: a robust water-splitting catalyst with benchmark characteristics

Schäfer

Sadaf

Walder

et al. 2015

Energy Environ. Sci.

197

207

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The oxygen evolution reaction (OER) is known as the efficiency-limiting step for the electrochemical cleavage of water mainly due to the large overpotentials commonly used materials on the anode side cause. Since Ni-Fe oxides reduce overpotentials occurring in the OER dramatically they are regarded as anode materials of choice for the electrocatalytically driven water-splitting reaction. We herewith show that a straightforward surface modification carried out with AISI 304, a general purpose austenitic stainless steel, very likely, based upon a dissolution mechanism, to result in the formation of an ultra-thin layer consisting of Ni, Fe oxide with a purity > 99%. The Ni enriched thin layer firmly attached to the steel substrate is responsible for the unusual highly efficient anodic conversion of water into oxygen as demonstrated by the low overpotential of 212 mV at 12 mA/cm 2 current density in 1 M KOH, 269.2 mV at 10 mA/cm 2 current density in 0.1 M KOH respectively. The Ni, Fe-oxide layer formed on the steel creates a stable outer sphere, and the surface oxidized steel samples proved to be inert against longer operating times (> 150 ks) in alkaline medium. In addition Faradaic efficiency measurements performed through chronopotentiometry revealed a charge to oxygen

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Section: The Catalytic Active Speciessupporting

confidence: 92%

Stainless steel made to rust: a robust water-splitting catalyst with benchmark characteristics

Schäfer

Sadaf

Walder

et al. 2015

Energy Environ. Sci.

197

207

View full text Add to dashboard Cite

show abstract

“…This may be caused by diffusion of the charge species (H + /OH -) into the oxide film through defects and pores [23,24]. The capacitive behaviour of the electrode/electrolyte interface at low frequencies is common in the case of ion intercalation into an inorganic/polymer matrix [25]. In contrast, when E C 0.5 V (in the O 2 evolution region), the low frequency end of the Nyquist plot gives a semicircle, the diameter of which decreases with increasing E (or overpotential, g).…”

Section: Electrochemical Impedance Spectroscopy (Eis)mentioning

confidence: 99%

Electrochemical impedance spectroscopy investigation of spinel type cobalt oxide thin film electrodes in alkaline medium

et al. 2008

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Spinel type Co 3 O 4 thin films, for the oxygen evolution reaction (OER) in 1 M KOH, have been prepared, on stainless steel supports, using the thermal decomposition method at 400°C. The electrochemical behaviour of the oxide film/1 M KOH interface was investigated by cyclic voltammetry and impedance techniques. The impedance measurements were carried out at different positive potentials, from the open circuit potential to a potential in the OER region and the electrical equivalent circuit, L (R 1 Q 1 ) (R 2 Q 2 ) (R 3 Q 3 ) was used to fit the experimental results. At each potential, a good correlation between experimental and simulated data is found, thereby validating the proposed equivalent circuit model. The roughness factor value determined in the potential region where the charge transfer reaction is negligible is similar to that obtained by cyclic voltammetry, with a value of 70 ± 2.

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“…In this regard, tailoring the electrode surface with nanostructures of transition metal oxides resulted in interesting electrocatalytic enhancement towards the OER by orders of magnitude compared to that obtained at unmodified (i.e., bare) electrodes [24][25][26][27][28]. Recently, we have reported on the significantly enhanced electrocatalytic activity of nickel oxide nanoparticle-modified electrodes towards the OER in alkaline medium [25].…”

Section: Introductionmentioning

confidence: 98%

Enhanced electrolytic generation of oxygen gas at binary nickel oxide–cobalt oxide nanoparticle-modified electrodes

Sadiek

Mohammad

Elshakre

et al. 2012

J Solid State Electrochem

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This study addresses the enhancement of the oxygen evolution reaction (OER) on glassy carbon, Au, and Pt electrodes modified with binary catalysts composed of nickel oxide nanoparticles (nano-NiO x ) and cobalt oxide nanoparticles (nano-CoO x ). Binary NiO x /CoO x -modified electrodes (with NiO x initially deposited) show a high catalytic activity and a marked stability which far exceeds that obtained at the individual oxide-modified electrodes. This enhancement is demonstrated by a marked negative shift (more than ca. 600 mV) in the onset potential of the OER compared to that obtained at the unmodified electrodes. The modified electrodes show a significantly higher long-term stability, over a period of 5 h of continuous electrolysis, without any significant loss of activity towards the OER in alkaline medium. The influence of the solution pH, the loading level, and sequence of deposition of each oxide on the electrocatalytic activity of the modified electrodes is addressed with an aim to maximize the catalytic activity of the modified electrodes towards the OER. SEM imaging is used to disclose the size and morphology of the fabricated nano-NiO x and nano-CoO x binary catalysts at the electrode surface.

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Effect of partial substitution of Cr on electrocatalytic properties of CoFe2O4CoFe2O4 towards O2O2-evolution in alkaline medium☆

Cited by 39 publications

References 42 publications

Stainless steel made to rust: a robust water-splitting catalyst with benchmark characteristics

Stainless steel made to rust: a robust water-splitting catalyst with benchmark characteristics

Electrochemical impedance spectroscopy investigation of spinel type cobalt oxide thin film electrodes in alkaline medium

Enhanced electrolytic generation of oxygen gas at binary nickel oxide–cobalt oxide nanoparticle-modified electrodes

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