The Effect of Solution pH and Temperature on the Oscillatory Electro-Oxidation of Formic Acid on Platinum

Autor(es)

Hartl, Fabian W. ^[1] ; Varela, Hamilton ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Chem Sao Carlos, Dept Phys Chem, POB 780, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: CHEMISTRYSELECT; v. 2, n. 27, p. 8679-8685, SEP 21 2017.
• Citações Web of Science: 3

Resumo

The effect of solution pH on the electro-oxidation of formic acid has been discussed in terms of the key role of solution HCOO- species on the third parallel pathway, besides the indirect oxidation via and a possible third pathway involving bridge-bonded formate. In this contribution we study the role of solution pH and temperature on the oscillatory electro-oxidation of formic acid on platinum. Highest oxidation rates were found roughly from pH from 5 to 12, whereas no potential oscillations were recorded between pH 4 and 11, probably due to the very fast rates of the main current carrier step: the direct oxidation of solution formate. The decrease in the oxidation rates at high pH also results in the appearance of oscillations at pH 13 and 14, which were considerably distinct than those found in acidic media. The system was further studied from 25 to 50 degrees C at nine temperatures, and activation energies were estimated in all cases. Overall, the discussion was based in the fact that, under oscillatory regime, many reaction steps are simultaneously active and this is the cause of the peculiarities found in this system, in contrast to that under conventional conditions. (AU)

• Processo FAPESP: 13/16930-7 - Eletrocatálise V: processos eletrocatalíticos de interconversão entre as energias química e elétrica
• Beneficiário: Edson Antonio Ticianelli
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 14/08030-9 - Eletrocatálise em regime oscilatório: espectroscopia IR in situ na configuração ATR-SEIRAS
• Beneficiário: Fabian Hartl
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto