Nickel-molybdenum catalysts fabricated by mechanical alloying and spark plasma sintering

S.D. De la Torre , Dariusz Oleszak , A. Kakitsuji , K. Miyamoto , H. Miyamoto , R. Martı́nez-S. , F. Almeraya-C , A. Martı́nez-V. , D. Rios-J.

Abstract

The low energy ball milling process has been used to fabricate Ni–43at.\%Mo based electro-active powder. Nanometre-sized Mo particles have been embedded into an agglomerated amorphous matrix. The spark plasma sintering (SPS) process has been used to densify the powder in \<6 min at heating rates of about 250°C min−1 from 400 to 1300°C, applying loads of 120 MPa. High performance porous nickel electrodes having new phases with a particle size range between 1.0 and 8.7 μm have been obtained after rapid SPS operations. Potentiodynamic polarisation techniques have been used to characterise the hydrogen evolution reaction (HER) in KOH 30\% solution at 70°C. The cathodic-Tafel slopes βc have been found from 25 to 150 mV dec−1 and appear to decrease as the open porosity of electrodes enlarges. It has been confirmed that the larger porosity (surface roughness) of the electrodes the larger exchange current density I0 and so their electrocatalytic activity to polarise the HER. In addition to a large surface area and a particle size distribution, the presence of metastable Ni–Mo phases coexisting with MoO2 and the existence of localised galvanic couples are remarkable features conferring the electrodes with unusual reactivity. In this study the microstructure and densification attained are reported on, as well as the preliminary polarisation analysis of these electrodes.
Author S.D. De la Torre - [Technology Research Institute of Osaka Prefecture]
S.D. De la Torre,,
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, Dariusz Oleszak (FMSE / DCFM)
Dariusz Oleszak,,
- Division of Construction and Functional Materials
, A. Kakitsuji - [Technology Research Institute of Osaka Prefecture]
A. Kakitsuji,,
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, K. Miyamoto - [Technology Research Institute of Osaka Prefecture]
K. Miyamoto,,
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, H. Miyamoto - [Technology Research Institute of Osaka Prefecture]
H. Miyamoto,,
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, R. Martı́nez-S. - [Centro de Investigacion en Materiales Avanzados]
R. Martı́nez-S.,,
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, F. Almeraya-C - [Centro de Investigacion en Materiales Avanzados]
F. Almeraya-C,,
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, A. Martı́nez-V. - [Centro de Investigacion en Materiales Avanzados]
A. Martı́nez-V.,,
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, D. Rios-J. - [Centro de Investigacion en Materiales Avanzados]
D. Rios-J.,,
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Journal seriesMaterials Science and Engineering A-Structural Materials Properties Microstructure And Processing, ISSN 0921-5093
Issue year2000
Vol276
No1–2
Pages226-235
Keywords in Englishcatalysts, electrodes, hydrogen, Mechanical alloying, Ni–Mo, Spark plasma sintering (SPS)
ASJC Classification2210 Mechanical Engineering; 2211 Mechanics of Materials; 3104 Condensed Matter Physics; 2500 General Materials Science
DOIDOI:10.1016/S0921-5093(99)00156-2
URL http://www.sciencedirect.com/science/article/pii/S0921509399001562
Score (nominal)30
Score sourcejournalList
Publication indicators WoS Citations = 34; Scopus Citations = 36; Scopus SNIP (Source Normalised Impact per Paper): 2000 = 1.084; WoS Impact Factor: 2006 = 1.49 (2) - 2007=1.931 (5)
Citation count*40 (2014-08-23)
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* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.
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