Electrochemical Oxidation of Oxalic Acid at Different Anode Materials: Applicability of Electroanalysis for Monitoring OA Degradation

Gonzalves-Araújo, Eliane; Oliveira, Gustavo Rodrigues; Santos, Enilson Medeiros dos; Martínez‐Huitle, Carlos A.; Fernandes, Nedja Suely

doi:10.1149/1.4704978

Cited by 2 publications

(1 citation statement)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, HCOOH and H 2 C 2 O 4 species are oxidized and can be decomposed in one of the possible ways, resulting in CO and CO 2 formation. 22,23 According to general ideas of electrochemical metal oxidation, water can also be oxidized, producing oxygen. 2 So, one can conclude that a thin film should form on the surface of the samples at the initial stage of Al anodizing in the mixed electrolyte containing formic and oxalic acids acid with or without ammonium heptamolybdate additive.…”

Section: Resultsmentioning

confidence: 99%

Effect of Oxalic Acid Additives on Aluminum Anodizing in Formic Acid Containing Ammonium Heptamolybdate

Chernyakova,

Klimas,

Karpicz

et al. 2023

J. Electrochem. Soc.

View full text Add to dashboard Cite

We report on a systematic study of the role of oxalic acid additives in aluminum anodizing in formic acid containing ammonium heptamolybdate. Adding oxalic acid in a concentration range of 5–20 mM to the 0.4 M formic acid solution containing 0.03 M ammonium heptamolybdate improves anodic film growth, increasing the film thickness and smoothing strongly wavy interface between the film and aluminum, and adding 100 mM of oxalic acid results in an almost complete block of the regular anodic film formation. In the case of aluminum anodizing in formic acid, the ammonium heptamolybdate additive prevents aluminum dissolution more effectively than only oxalic acid. The role of oxalic acid in this process is only to improve film growth and morphology. However, ammonium heptamolybdate improves film growth by increasing its thickness. Linear sweep voltammetry studies combined with scanning electron microscopy investigations of alumina growth show that in heptamolybdate-containing electrolytes, a thin porous alumina film is formed at the beginning of the process. Then, when the electrolyte oxidation potential is reached, the thin film on the surface breaks resulting in a significant increase in the anodizing surface, and anodic oxide begins to grow rapidly.

show abstract

Section: Resultsmentioning

confidence: 99%