Kinetics of the Hydrogen Evolution Reaction on Mild Steel and Nickel Cathodes in Concentrated Sodium Hydroxide Solutions

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