Hydrogen Production on Aluminum in Alkaline Media

The corrosion behavior and hydrogen generation on aluminum in NaOH solutions are followed up using different techniques. The rates of Al2O3 film destruction, metal dissolution, and hydrogen gas production are dependent on the alkali amount and the solution temperature. The existence of two capacitive semicircles at high and low frequencies confirm the charge transfer process on the metal surface. The existence of an inductive loop at intermediate frequencies emphasizes the surface charge due to the building up of oxide film at the Al/Al2O3 interface. Low values of free energy of activation of these processes E-a indicate that these processes are controlled by a diffusion step. The positive values of Delta H-a reflect the endothermic nature of the activation processes, while the negative values of Delta S-a indicate a decreased disordering of a dissociation step.

Automated summary

The corrosion behavior and hydrogen generation on aluminum in NaOH solutions are dependent on the alkali amount and the solution temperature, with rates of Al2O3 film destruction, metal dissolution, and hydrogen gas production being key factors. Electrochemical tests confirm the charge transfer process on the metal surface and the accumulation of oxide film at the Al/Al2O3 interface.