Rrde Studies of Glycerol Electro-Oxidation: Local pH Variation and Oscillatory Dynamics

Autor(es)

Zulke, A. ; Perroni, P. ; Machado, E. G. ; Varela, H. ; Manivannan, M ; Narayan, S ; Kostecki, R ; Johnson, C ; Atanassov, PB

• Tipo de documento: Artigo Científico
• Fonte: SOLID OXIDE FUEL CELLS 10 (SOFC-X), PTS 1 AND 2; v. 77, n. 11, p. 8-pg., 2017-01-01.

Resumo

Using Pt-disk-Pt-ring electrodes we investigated glycerol electro-oxidation in alkaline media under both conventional and oscillatory conditions. The estimation of pH variation was done by polarizing the ring electrode at 100mV vs. RHE. The local depletion of Off (variation in hydronium concentration) during oxidative steps at the disk is seen by the cathodic currents at the ring associated with hydrogen evolution, whose equilibrium potential (Nernstian potential) is shifted due to its well-known pH dependence. Typical voltammetric experiments at 20mV.s(-1) in hydrodynamic conditions reveal Delta pH of around 1 unit. Higher rotation rates yielded lower peak currents. Under oscillatory conditions the situation is rather complicated as rotation of the electrode impacts on the critical population of intermediates required to sustain oscillations. It was only possible to obtain reproducible oscillatory dynamics under stationary conditions and pH variations seem not detectable by this technique. (AU)

• Processo FAPESP: 09/07629-6 - Eletrocatálise IV: aspectos fundamentais e aplicados dos processos eletrocatalíticos, bio-eletrocatálise e instabilidades cinéticas
• Beneficiário: Edson Antonio Ticianelli
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOEN - Temático
• Processo FAPESP: 12/21204-0 - Auto-organização temporal na eletro-oxidação de moléculas orgânicas pequenas: efeito da estrutura da superfície, da concentração de água e da temperatura
• Beneficiário: Bruno Alarcon Fernandes Previdello
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 13/06205-3 - Instabilidades cinéticas na interface eletrodo/solução: medida e variação da temperatura superficial
• Beneficiário: Alana Aragon Zulke
• Modalidade de apoio: Bolsas no Brasil - Doutorado