Ni/NiO nanosheets for alkaline hydrogen evolution reaction: In situ electrochemical-Raman study

Faid, Alaa Y.; Barnett, Alejandro Oyarce; Seland, Frode; Sunde, Svein

doi:10.1016/j.electacta.2020.137040

Cited by 192 publications

(124 citation statements)

References 71 publications

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“…At 0 V vs RHE there are still traces of peaks related to oxide/hydroxide species of nickel and iron in the spectrum. For a more detailed interpretation, see ref ( 38 ). In the figure we have indicated the approximate peak positions for the various species by the corresponding chemical formulas.…”

Section: Resultsmentioning

confidence: 99%

“…In-situ Raman spectroscopy was performed in a specially designed (in-house) cell of Teflon fitted with a quartz window through which the laser beam from a Witec alpha300 R Confocal Raman imaging system (equipped with Zeiss EC Epiplan 10× objective lens) was admitted toward the sample. 38 The laser power was 20 mW, and the laser wavelength 532 nm. The measurements were made in Ar-saturated 0.1 mol dm –3 KOH (semiconductor grade, 99.99% purity, Sigma-Aldrich).…”

Section: Methodsmentioning

confidence: 99%

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Effect of the Synthetic Method on the Properties of Ni-Based Hydrogen Oxidation Catalysts

Davydova

Manikandan

Dekel

et al. 2021

ACS Appl. Energy Mater.

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The latest progress in alkaline anion-exchange membranes has led to the expectation that less costly catalysts than those of the platinum-group metals may be used in anion-exchange membrane fuel cell devices. In this work, we compare structural properties and the catalytic activity for the hydrogen-oxidation reaction (HOR) for carbon-supported nanoparticles of Ni, Ni 3 Co, Ni 3 Cu, and Ni 3 Fe, synthesized by chemical and solvothermal reduction of metal precursors. The catalysts are well dispersed on the carbon support, with particle diameter in the order of 10 nm, and covered by a layer of oxides and hydroxides. The activity for the HOR was assessed by voltammetry in hydrogen-saturated aqueous solutions of 0.1 mol dm –1 KOH. A substantial activation by potential cycling of the pristine catalysts synthesized by solvothermal reduction is necessary before these become active for the HOR; in situ Raman spectroscopy shows that after activation the surface of the Ni/C, Ni 3 Fe, and Ni 3 Co catalysts is fully reduced at 0 V, whereas the surface of the Ni 3 Cu catalyst is not. The activation procedure had a smaller but negative impact on the catalysts synthesized by chemical reduction. After activation, the exchange-current densities normalized with respect to the ECSA (electrochemically active surface area) were approximately independent of composition but relatively high compared to catalysts of larger particle diameter.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Effect of the Synthetic Method on the Properties of Ni-Based Hydrogen Oxidation Catalysts

Davydova

Manikandan

Dekel

et al. 2021

ACS Appl. Energy Mater.

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“…As shown in Figure 3, the photoresponse current increases and the carrier recombination is suppressed by the use of the metal cocatalyst (Figure S6, Supporting Information). [ 18–20 ]…”

Section: Resultsmentioning

confidence: 99%

Flexible Photocatalytic Electrode Using Graphene, Non‐noble Metal, and Organic Semiconductors for Hydrogen Evolution Reaction

et al. 2021

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Two kinds of visible light‐responsible organic semiconductors (epindolidione [EPI] and fluorinated EPI [2F‐EPI]) are synthesized. The solar hydrogen evolution photocatalytic electrode properties of the organic semiconductors are investigated and the heterostructure effect caused by manipulating the order of the deposition of 2F‐EPI and EPI is found, which increased the photoresponse current by reducing the carrier recombination of photoexcited electrons and holes. In addition, it is found that the deposition of Ni metal on the organic semiconductors further enhanced the photoresponse current and increased the durability of the organic semiconductor photocatalyst. Finally, a flexible photocatalytic electrode using graphene, organic semiconductors, and non‐noble metal cocatalyst for solar hydrogen generation is prepared. A transparent flexible electric conductive film is prepared by transfer of a graphene sheet on the polymer film. The graphene electrode is coated by two kinds of organic semiconductors layer by layer to reduce recombination of photoexcited electrons and holes. Ni metal particles are deposited on the surface of the organic semiconductor layer as a cocatalyst to improve the photocatalytic property and durability of organic semiconductors. A clear photoresponse current (about 4 μA cm−2) of the flexible photocatalytic electrode under the simulated solar light (AM 1.5 G, 100 mW cm−2) is observed.

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“…They include compounds with elements of the VA and VIA groups of the Periodic Table of the Elements. It has been shown that high activity is exerted by phosphides, [9–16] nitrogen doped species, [17,18] sulfides, [19–21] selenides, [22,23] tellurides, [24,25] and oxides/hydroxides [26–31] …”

Section: Introductionmentioning

confidence: 99%

“…However, oxides/hydroxides can be reduced under conditions of HER, hence there is a need to make anodic products sufficiently stable. Raman spectroscopy demonstrated that the high initial HER activity might be due to β‐Ni(OH) 2 species which, however, vanishes after a prolonged cathodic polarization [31] . Papers [33–35] showed that extended durability can be obtained by electrochemical treatments at high anodic potentials to form oxides Ni 3 O 4 , Ni 2 O 3 , and/or NiO 2 .…”

Section: Introductionmentioning

confidence: 99%

Understanding the Enhancement of Electrocatalytic Activity toward Hydrogen Evolution in Alkaline Water Splitting by Anodically Formed Oxides on Ni and C‐containing Ni

2021

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Nickel oxides/hydroxides are active electrocatalysts for the hydrogen evolution reaction (HER) in alkaline water electrolysis. A durable activity of Ni with Ni(OH)2 was observed mainly on porous substrates, such as nickel foam or carbon cloth. Herein, we examined the effect of anodic oxidation on the HER using smooth samples of Ni, Ni with graphene, and Ni with C introduced by a low‐temperature plasma treatment. Electrochemical measurements in 1.0 M KOH showed that a strong activation toward HER was achieved by voltammetric cycling to potentials of the formation of Ni3O4, Ni2O3, and/or NiO2. The presence of C enhanced this activation. The effect of C was explained by the accumulation of larger amounts of these products as a result of a deteriorated passivity, their higher compactness (demonstrated by higher impedance), and the longer durability under conditions of HER (revealed by a slower cathodic reduction). The durability of oxides in porous C structures can be explained by anodic potentials in pores owing to the ohmic potential drop. It is proposed that anodic oxidation might be used for the reactivation of Ni cathodes for water electrolysis.

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Ni/NiO nanosheets for alkaline hydrogen evolution reaction: In situ electrochemical-Raman study

Cited by 192 publications

References 71 publications

Effect of the Synthetic Method on the Properties of Ni-Based Hydrogen Oxidation Catalysts

Effect of the Synthetic Method on the Properties of Ni-Based Hydrogen Oxidation Catalysts

Flexible Photocatalytic Electrode Using Graphene, Non‐noble Metal, and Organic Semiconductors for Hydrogen Evolution Reaction

Understanding the Enhancement of Electrocatalytic Activity toward Hydrogen Evolution in Alkaline Water Splitting by Anodically Formed Oxides on Ni and C‐containing Ni

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