Development of electrode morphologies of interest in electrocatalysis. Part 1: Electrodeposited porous nickel electrodes

Cu-Ni alloy layers with a bimodal porosity -a spongy material made of submicron dendrites, featuring macroscopic pores tens of microns large -can be deposited from baths containing the metal ions, sodium citrate and ammonium sulfate, using large current densities (−3 A cm −2 ) producing vigorous hydrogen evolution. Alloys with a broad range of compositions are obtained using baths with different Cu(II)/Ni(II) concentration ratios. Voltammetric experiments of nitrate reduction at compact and porous Cu-Ni RDEs show, in the latter case, lower overvoltage and higher peak currents, resulting from enhanced transport and improved catalytic activity. © 2013 The Electrochemical Society. [DOI: 10.1149/2.004311eel] All rights reserved.Manuscript submitted July 18, 2013; revised manuscript received August 6, 2013. Published August 21, 2013 Porous electrodes are a topic of intense current interest.1-13 Among the traditional preparation methods, dealloying is applicable only in a few cases and the final materials contain inclusions of the less noble metal.1,2 Modern approaches based on electrodeposition within rigid templates 3 -based e.g. on polymers, 4,5 silica spheres, 6 alumina membranes 7 -warrant a good control of shape, size and organization of the inner porosity, but require final removal of the template and usually provide uniform tiny porosity that may not improve electrode performances in diffusion controlled processes. 6A convenient alternative procedure is deposition in presence of copious hydrogen evolution: the gas bubbles act as a dynamic, faint template that disappears after switching off the current and allows a single step preparation. The method has been tested for the deposition of several porous metals including Sn, 8 Cu, [8][9][10]11,12 Ag and Au 13and typically results in a bimodal porosity of potential interest in electrocatalysis, as the tiny structures with dimensions down to tens of nanometers provide a large surface area, while macropores tens of microns large may ensure enhanced mass transport. The extension of this approach to deposition of porous alloys of controlled composition is not obvious and only a few cases have been described. 14,15 We have recently reported on the deposition of compact Cu-Ni alloys with a large range of compositions and on their strong activity in nitrate reduction. 16 We propose in this paper the deposition of porous Cu-Ni electrodes that show improved characteristics in this reaction and that might provide, at low cost, a good electrode material in applications like wastewater treatment and electroanalysis. 17 ExperimentalThe single compartment cell used for deposition was equipped with a Pt wire counter electrode wound as a spiral around the inner wall. RDE electrodes were obtained from Cu rods (Goodfellow, 99.999% purity), or Nb rods (Goodfellow, 99.9%) inserted in a PTFE sheath; their geometric area was 0.317 cm 2 and 0.247 cm 2 , respectively. Nb RDEs were used for EDS analyses, Nb sheets (Goodfellow, 99.5%) for deposition of samples devoted to XRD analyses. All ...

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“…The method has been tested for the deposition of several porous metals including Sn, 8 Cu, [8][9][10]11,12 Ag and Au…”

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confidence: 99%

Electrodeposition of Cu-Ni Alloy Electrodes with Bimodal Porosity and Their Use for Nitrate Reduction

Mattarozzi

Cattarin

Comisso

et al. 2013

ECS Electrochemistry Letters

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“…The current for hydrogen evolution at more negative potentials reached 60-70 % of the total current, which is in excellent agreement with the values obtained during the electrodeposition of copper in the hydrogen co-deposition range. Simultaneously, the honeycomb-like structures of nickel [44] were very similar to those of copper. Under the determined electrodeposition conditions, very branchy nickel dendrites were formed [14] which were more similar to the dendrites of intermediate metals than those belonging to the group of normal metals.…”

Section: The Transitional Characteristics Of the Intermediate Metals mentioning

confidence: 67%

Comparative analysis of the polarization and morphological characteristics of electrochemically produced powder forms of the intermediate metals

Nikolić

Živković²,

Jokić³

et al. 2014

Maced. J. Chem. Chem. Eng.

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The polarization and morphological characteristics of powder forms of the group of the intermediate metals were examined by the analysis of silver and copper electrodeposition processes at high overpotentials. The pine-like dendrites constructed from the corncob-like forms, which are very similar to each other, were obtained by electrodeposition of these metals at the overpotential belonging to the plateaus of the limiting diffusion current density. A completely different situation was observed by the electrodeposition of silver and copper at the overpotential outside the plateaus of the limiting diffusion current density in the zone with the fast increase in current density with the overpotential. Silver dendrites, which were very similar to silver and copper dendrites obtained inside the plateaus of the limiting diffusion current density, were obtained at the overpotential outside the plateau. Due to the lower overpotential for hydrogen evolution for copper, hydrogen produced during the copper electrodeposition process strongly affected the surface morphology of copper. The same shape polarization curves with completely different surface morphologies of Cu and Ag electrodeposited at overpotentials after the inflection point clearly indicate the importance of morphological analysis in the investigation of polarization characteristics of the electrodeposition systems. The role of hydrogen as a crucial parameter in the continuous change of copper surface morphology from dendrites to honeycomb-like structures was investigated in detail. On the basis of this analysis, the transitional character of the intermediate metals between the normal and inert metals was considered. The typical powder forms characterising electrodeposition of the intermediate metals were also defined and systematized.Keywords: electrodeposition; copper; silver; dendrite; hydrogen; pores; cauliflower-like forms СПОРЕДБА НА ПОЛАРИЗАЦИОНИТЕ И МОРФОЛОШКИТЕ КАРАКТЕРИСТИКИ НА ЕЛЕКТРОХЕМИСКИ СОЗДАДЕНИ ПРАШКОВИДНИ ОБЛИЦИ НА ИНТЕРМЕДИЈАРНИ МЕТАЛИПреку анализа на процесите на електродепозиција на сребро и бакар при високи пренапони беа испитувани и споредувани поларизационите и морфолошките карактеристики на прашоци од интермедијарни метали. При електродепозиција на овие метали со пренапони што припаѓаат на платото на гранична дифузиона густина на струјата, беа добиени дендрити во вид на бор изградени од елементи слични на кочан од пченка, кои се многу слични еден на друг. Наполно поинаква состојба беше утврдена при електродепозиција на овие метали со пренапони надвор од платото на гранична дифузиона густина на струја во делот на брз пораст на густината на струјата. Дендрити на среброто, многу слични на оние на дендритите на сребро и бакар добиени при пренапони што припаѓаат на платото на гранична дифузиона густина на струјата, беа добиени при пренапони надвор од оние на платото. Поради помалиот пренапон за издвојување на водород врз бакар, водородот создаден врз овој метал нагласено ја менуваше морфологијата на површината на бакарот. Истиот облик на п...

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“…The pore size tends to increase as the thickness of the deposited film increases due to hydrogen bubble coalescence, and this creates a graded structure. This method has been used to create foams of nickel, [43,44] copper, [45,46] and their alloys. [47] DHBT has many interesting adaptions to control deposition characteristics, but the rate and scale of production is relatively limited (e.g., film thickness often 100s of microns or less).…”

Section: Discussionmentioning

confidence: 99%

Solid State Foaming of Nickel, Monel, and Copper by the Reduction and Expansion of NiO and CuO Dispersions

et al. 2018

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Nickel and its alloys are useful in a range of applications, and nickel foams have increased in popularity for functional applications, such as electrodes. Despite their versatility and interest for burgeoning technologies, there is only one well-developed method for producing porous nickel commercially. This work introduces a simple method for creating porosity in nickel and Monel (70% Ni, 30% Cu) that results in sub-micron to micron-scale pores and grains. This is accomplished by creating oxide dispersions in the metallic matrix and then reducing those oxides at elevated temperature to form pores. It is found that nickel and Monel reach maximum porosity at 800 C withMonel reaching a higher overall porosity (33% vs. 25% for Ni), whereas Cu exhibited 40% porosity under the same conditions. Varied matrix and oxide pairings are examined microstructurally, and the effects of matrix strength, oxide chemistry, and other factors are considered to determine factors in pore development. Uniquely, this method produces pores within individual metallic particles, so this porosity can be added to other powder methods of solid state foaming to enhance the performance in functional applications.

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Development of electrode morphologies of interest in electrocatalysis. Part 1: Electrodeposited porous nickel electrodes

Cited by 160 publications

References 15 publications

Electrodeposition of Cu-Ni Alloy Electrodes with Bimodal Porosity and Their Use for Nitrate Reduction

Electrodeposition of Cu-Ni Alloy Electrodes with Bimodal Porosity and Their Use for Nitrate Reduction

Comparative analysis of the polarization and morphological characteristics of electrochemically produced powder forms of the intermediate metals

Solid State Foaming of Nickel, Monel, and Copper by the Reduction and Expansion of NiO and CuO Dispersions

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