Kinetics of the hydrogen evolution reaction on mild steel and nickel cathodes in concentrated sodium hydroxide solutions

Journal Article · Mon Nov 01 00:00:00 EST 1982 · J. Electrochem. Soc.; (United States)

DOI:https://doi.org/10.1149/1.2123588· OSTI ID:5758175

Brown, A P; Krumpelt, M; Loutfy, R O; Yao, N P

Data are reported at 288 to 358 K for both smooth and roughened electrode surfaces up to current densities of about 0.3 A/cm/sup 2/. Tafel plots for the nickel cathodes are linear over the whole current density range studied. The transfer coefficient, ..beta.., has an average value of 0.54 and is unaffected by varying either the caustic concentration, the temperature, or the surface roughness of the electrode. With the mild steel cathodes, the Tafel plots show two linear regions with the inflection point occurring at eta = 0.140 to -0.225 V. In the lower overpotential region, ..beta.. increases from about 0.5 to at least 1.4 with increasing caustic concentration and increasing temperature. This behavior is interpreted as being caused by a change in reaction mechanism and results from one of the reaction steps becoming reduced in rate. The ability of the caustic concentration or the temperature to affect the reaction mechanism is amplified by roughening the electrode surface. For the linear regions in the Tafel plots at high overpotentials, the slopes are almost invariant to changes in the caustic concentration, the temperature, or the surface roughness. The transition between the two Tafel regions appears to be caused by a change in the electrode surface resulting from the reduction of a surface oxide, possibly FeOH. The dependence of the inflection point potential on the experimental variables is analyzed in terms of this potential being equivalent to the equilibrium potential of the inferred surface redox reaction.

• Research Organization: Argonne National Lab., IL
• OSTI ID: 5758175
• Journal Information: J. Electrochem. Soc.; (United States), Vol. 129:11
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
08 HYDROGEN
HYDROGEN PRODUCTION
CHEMICAL REACTION KINETICS
AQUEOUS SOLUTIONS
CATHODES
CHEMICAL COMPOSITION
CURRENT DENSITY
ELECTRIC POTENTIAL
ELECTROCHEMISTRY
ELECTROLYSIS
ELECTROLYTES
HYDROGEN
MEDIUM TEMPERATURE
NICKEL
OVERVOLTAGE
QUANTITY RATIO
ROUGHNESS
SODIUM HYDROXIDES
STEELS
TEMPERATURE DEPENDENCE
ALKALI METAL COMPOUNDS
ALLOYS
CHEMISTRY
DISPERSIONS
ELECTRODES
ELEMENTS
HYDROGEN COMPOUNDS
HYDROXIDES
IRON ALLOYS
IRON BASE ALLOYS
KINETICS
LYSIS
METALS
MIXTURES
NONMETALS
OXYGEN COMPOUNDS
REACTION KINETICS
SODIUM COMPOUNDS
SOLUTIONS
SURFACE PROPERTIES
TRANSITION ELEMENTS
400400* - Electrochemistry
080101 - Hydrogen- Production- Electrolysis