Impedance studies of hydrogen evolution on NiP alloys

• Published in: Electrochimica acta Vol. 47; no. 13; pp. 2065 - 2069
• Main Authors: Królikowski, A., Wiecko, A.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 25.05.2002; Elsevier
• Subjects: Chemistry; Electrochemical impedance; Electrochemistry; Exact sciences and technology; General and physical chemistry; Hydrogen evolution; Miscellaneous; NiP alloys; Potentiodynamic polarisation; Potentiostatic polarisation; Study of interfaces; NiP alloys; Potentiostatic polarisation; Electrochemical impedance; Potentiodynamic polarisation; Hydrogen evolution; Electrode impedance; Electrode electrolyte interface; Electrochemical activity; Experimental study; Electrochemical characteristic; Thin layer electrode; Electrochemical polarization; Chemical evolution; Hydrogen molecules; Kinetic parameter; Electrochemical reaction; Transfer resistance; Binary alloy
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/S0013-4686(02)00074-9

The hydrogen evolution reaction (HER) was studied on electrodeposited NiP alloys containing 7, 20 and 28 at.% P. Potentiodynamic, potentiostatic and impedance spectroscopy measurements were performed in 0.1 M H 2SO 4 solution. Kinetic parameters of the HER were derived from the analysis of polarisation and impedance data. Crystalline Ni7P alloy showed higher rate of the HER than amorphous Ni20P and Ni28P samples. However, this difference was small. The evident increase of the rate of the HER was observed for the crystalline Ni7P upon anodic prepolarisation. Under these circumstances the nature of the HER was changed and very high values of interfacial capacitance and much lower values of Tafel slope were found. These high values of interfacial capacitance can be assigned to the onset of a porous phosphate film on the alloy surface.