The hydrogen evolution reaction on amorphous nickel and cobalt alloys
1995; Elsevier BV; Volume: 20; Issue: 6 Linguagem: Inglês
10.1016/0360-3199(94)00068-b
ISSN1879-3487
AutoresM. Janete Giz, Germano Tremiliosi‐Filho, Ernesto R. González, S. Srinivasan, A.J. Appleby,
Tópico(s)Electrodeposition and Electroless Coatings
ResumoThe mechanism of the hydrogen evolution reaction (HER) on Ni70P30, Co72P28, Ni40Co23P37 and Ni72Fe1P27 was studied by impedance spectroscopy and steady-state polarization measurements. Only the Ni-Fe-P presents a good electrocatalytic activity with an overpotential ≈200 mV lower than that for mild steel or Ni (the traditional materials used as cathodes in water electrolysers). Impedance studies of the HER were carried out on these amorphous alloys and it was concluded that Ni-Fe-P is the only material to present a Volmer-Heyrovsky mechanism with the Heyrovsky step being the r.d.s. In contrast, on Co-P, Ni-P and Ni-Co-P the mechanism is Volmer-Tafel with the Volmer step being the r.d.s. From the rate constants the following catalytic sequence was determined: Ni-Fe-P > Co-P > Ni-Co-P > Ni-P.
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