engleski

Impedance Spectroscopy Characterization of Electrodeposited Ni-15Mo Catalyst Designed for the HER in Acid Solution: Modified Porous Model

Electrocatalytic properties of the Ni-15Mo catalyst electrodeposited on carbon substrate, designed for the hydrogen evolution reaction (HER) in an acid media, were investigated using polarization and electrochemical impedance spectroscopy (EIS) measurements. The composition and atomic ratio of the Ni-Mo electrodeposit were determined by quantitative energy dispersive X-ray spectrometry (EDAX). The presence of a very porous structure composed of micron and submicron sized particles, has been demonstrated by scanning electron microscopy (SEM). Kinetic parameters determined from the dc and ac results show excellent electrocatalytic activity of the porous Ni-15Mo catalyst in comparison with polycrystalline Ni. The effects influencing the frequency dispersions of the porous electrode at low frequencies were discussed on the basis of impedance measurements. The equivalent circuit analog to this situation is the finite – length transmission line terminated in a resistance. The penetration depth ( ) of an ac signal to pore length (lp) ratio as well as the penetrability coefficient ( ) were determined.

Electrocatalysis ; Hydrogen evolution ; Ni-Mo alloys ; Porous Electrode.

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