Electrochemical properties of Ni?P electrode materials modified with nickel oxide and metallic cobalt powders

Popczyk, Magdalena; Budniok, A.; Lasia, Andrzej

doi:10.1016/j.ijhydene.2004.03.026

Cited by 57 publications

(38 citation statements)

References 14 publications

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“…The positions of the first peaks (left-hand) in Ni-P and Ni-P/CeO 2 curves are 380 ℃ and 345 ℃, respectively. The first peak here represents the precipitation of Ni 3 P and/or Ni crystal phase from the coating, although the coating may be crystal or amorphous [5,6] . Meanwhile, these two peaks begin at 324℃ and 305℃, respectively, and this difference is due to the fact that the former's structure (nano-crystal＋amorphous) is more stable during high temperature scanning than the latter's pure amorphous structure, and the second phase precipitation process has lasted longer time (seen from first peak width).…”

Section: Resultsmentioning

confidence: 99%

“…Its chemical and mechanical property depends much on its microstructure and phosphorous content. Furthermore, the internal phase transformation of electroless Ni-P coating in high temperature environment has been widely studied by researchers [3][4][5][6] . It is commonly recognized that phosphorous content in Ni-P coating will determine the coating's structure in the range of normal ploy-crystalline, micro-crystalline, nano-crystalline and amorphous structure.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure and corrosive property of Ni-P/nano-CeO2 coating electrolessly prepared in acidic condition

Jin

Haihua

Felix

et al. 2010

J. Wuhan Univ. Technol.-Mat. Sci. Edit.

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Electroless Ni-P/nano-CeO 2 composite coating was prepared in acidic condition, and its microstructure and corrosive property were compared with its CeO 2 -free counterpart. Scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and differential scanning calorimeter (DSC) were used to examine surface morphology and microstructure of the coating. Aqueous corrosion was done in 3%NaCl＋5%H 2 SO 4 solution and high temperature oxidation was done at 750 in air. The results showed that Ni ℃ -P coating had partial amorphous structure mixed with nano-crystals, while the Ni-P/CeO 2 coating had perfect amorphous structure. At high temperature, Ni 3 P precipitation and Ni crystallization took place in both coatings at different temperatures. Aqueous corrosion property and high temperature oxidation property of the composite coating were remarkably improved due to the coating's microstructure change and the rare earth doping effect. During the co-deposition process, some Ce n＋ (n＝3, 4) ions may be adsorbed to metal/solution interface and hinder nickel deposition. Ni-P/CeO 2 coating's perfect amorphous structure results from the hindered crystal-typed deposition of nickel and the promoted deposition of phosphorous.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microstructure and corrosive property of Ni-P/nano-CeO2 coating electrolessly prepared in acidic condition

Jin

Haihua

Felix

et al. 2010

J. Wuhan Univ. Technol.-Mat. Sci. Edit.

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show abstract

“…5) and j in function of E (Fig. 1), was carried out by adjusting the rate constants k 1 3 [4,6,9] and are presented in Table 3. For all obtained coatings, the value of k 3 rate constant is at least of two orders smaller than values of k 1 and k 2 rate constants, suggesting that the main pathway for the HER at the above mentioned electrode materials is Volmer-Heyrovsky, and Tafel reaction has a small contribution to this process.…”

Section: Resultsmentioning

confidence: 99%

“…Assuming that the average double-layer capacitance of a smooth metal surface is 20 µF cm −2 , [10] the surface roughness factor was determined. Kinetics of hydrogen evolution process was determined on basis of the dependences of both the 1/R ct (inverse the charge-transfer resistance) and the total current density j, on overpotential E. The rate constants (k 1 …”

Section: Methodsmentioning

confidence: 99%

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The influence of molybdenum and silicon on activity of Ni + W composite coatings in the hydrogen evolution reaction

Popczyk

2008

Surface & Interface Analysis

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composite coatings were obtained by electrolytic codeposition of crystalline nickel from an electrolyte containing suspension of W, Mo and Si powders. These coatings were obtained under galvanostatic conditions, at the current density of j dep. = 0.100 A cm −2 and at the temperature of 338 K. Chemical composition of obtained coatings was determined by energy dispersive X-ray spectroscopy (EDS) method. The electrochemical activity of these coatings was studied in the process of hydrogen evolution reaction (HER) from 5 M KOH solution using steady-state polarisation and electrochemical impedance spectroscopy (EIS) methods. On the basis of the results of EIS measurements, the rate constants of the HER as well as the surface roughness factor were determined. It was found that Ni + W + Mo + Si composite coatings are characterised by enhanced electrochemical activity toward hydrogen evolution as compared with Ni + W + Si and Ni + W coatings. The reason for this is connected with the presence of additional composite components (W, Mo, Si). Thus, obtained coatings may be useful in application as electrode materials for the hydrogen evolution reaction.

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Ni + Mo composite coatings for hydrogen evolution reaction

Panek

Budniok

2008

Surface & Interface Analysis

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Composite Ni + Mo coatings were obtained by electrodeposition of Ni with Mo particles on a steel substrate from the nickel bath in which metallic Mo powder was suspended by stirring. Deposits were characterized by the presence of Mo particles embedded into the crystalline nickel matrix. Incorporation of metallic powder into electrolytic nickel matrix causes an increase in the real surface area of deposits.The composite coatings obtained were tested as electrode materials for hydrogen evolution reaction (HER) in an alkaline environment. Electrochemical characterization of the composites was carried out by steady-state polarization method and electrochemical impedance spectroscopy (EIS) measurements. It was ascertained, that Ni + Mo coatings are characterized by enhanced electrochemical activity for this process, which was confirmed by considerable decrease in the hydrogen evolution overpotential at the current density of 100 mA cm −2 − η 100 , by a nearly 170-260 mV compared to nickel electrode. Exchange current density j 0 increases with the increase in Mo content in the coatings.Based on the results of EIS measurements, the rate constants of the HER for Ni and Ni + 44%Mo coatings were determined. The calculated values of surface roughness factor R f allowed also to evaluate the influence of the real surface area on the electrocatalytic performance of these materials in an alkaline environment. It was stated that the improvement of the electrocatalytic performance of Ni + Mo composite coatings could be attributed to the increase in their real surface area as well as to the synergetic effect of molybdenum with the nickel matrix, as Ni/Mo materials are considered in literature, typical electrocatalysts for the HER.

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Electrochemical properties of Ni?P electrode materials modified with nickel oxide and metallic cobalt powders

Cited by 57 publications

References 14 publications

Microstructure and corrosive property of Ni-P/nano-CeO2 coating electrolessly prepared in acidic condition

Microstructure and corrosive property of Ni-P/nano-CeO2 coating electrolessly prepared in acidic condition

The influence of molybdenum and silicon on activity of Ni + W composite coatings in the hydrogen evolution reaction

Ni + Mo composite coatings for hydrogen evolution reaction

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