Hydrogen Evolution and Interface Phenomena on a Nickel Cathode in 30 w/o  KOH : I . Kinetics Parameters and Electrode Impedance Between 303 and 363 K

Abstract

The hydrogen evolution reaction (HER) is investigated on a nickel cathode in 30 weight percent (w/o) KOH containing KOH metallic impurities. It is shown that the hydrogen evolution mechanism does not vary substantially between 303 and 363 K and that the apparent heat of activation is 21 kJ tool-1. Reduction of the ferric impurity influences the log(i)-E curves for the HER at low cathodic overpotentials and at temperatures higher than 323 K. Impedance measurements during water electrolysis confirm the limited influence of thermal energy on charge transfer kinetics and underline the effect of the hydrogen bubble layer on the accessible surface. A pseudocapacitive effect observed at low cathodic overpotentials and at anodic overpotentials is tentatively explained by hydrogen electrosorption and nickel oxidation.

Preparation and electrochemical characterization of Ni+RuO2 composite cathodes of large effective area

“…These values are intermediate between current density values measured at Ni [53] and thermal RuO 2 [8,54] electrodes respectively. The overpotential measured at a current density of 100 mA cm −2 was 90 and 150 mV in 1 M NaOH and in 0.5 M H 2 SO 4 , respectively.…”

Water electrolysis in the presence of an ultrasonic field

“…The complex electrochemical interfacial phenomena in the three-zone region of gas bubbles, electrolyte and electrode significantly influence the energy efficiency of a hydrogen energy system. Many papers have described interesting phenomena that accompany gas bubble behavior at electrodes [1,3,[11][12][13][14][15][16][17]. According to these reports, water electrolysis was influenced by the combined effect of bubble surface coverage and bubble dispersion.…”

Electrodeposited Co-Ni-Fe-C Alloys for Hydrogen Evolution in a Hot 8 kmol&middot;m<SUP>&minus;3</SUP> NaOH

“…Enhancement of cathodic activity of nickel and cobalt for electrolytic hydrogen evolution has been carried out by the formation of alloys such as Ni-S, 1) Raney Ni, 2) Ni-Mo, [3][4][5][6][7][8] Raney Ni-RuO, 2,9) Ni-Sn, 10) Ni-Mo-O, 11,12) Ni-Fe-C, 13,14) CoMo 15) and Co-Fe. 16) Among them, electrodeposited Ni-Fe-C alloys have the highest activity for hydrogen evolution in hot alkaline solutions and excellent durability: The overpotential for hydrogen evolution at the current density of 1000 Am À2 in 8 kmolÁm À3 NaOH at 90 C was less than 100 mV.…”