Tuning oscillatory time-series evolution by Pt(111)-OHad stabilization

Author(s)

da Silva, Kaline N. ; Sitta, Elton

• Document type: Journal article
• Source: Journal of Solid State Electrochemistry; v. 24, n. 8, p. 6-pg., 2020-03-26.

Abstract

Controlling the Pt(111)-OHad stability by means of noncovalent interactions with hydrated cations, it was possible to modify natural changes in the galvanostatic time-series collected during ethylene glycol electro-oxidation reaction. These modifications, also known as drift, include maximum potential in each oscillation cycle, oscillation patterns, and frequency changes. The phenomenon was investigated in a temperature range from 5 to 20 degrees C and allows us to infer about the sensitiveness of time-series in the presence of distinct alkaline cations. The stable OHad layer in the presence of Li+ induces lower drift in the time-series, resulting in a longer time-series with oscillatory behavior. On the other hand, once the OHad layer is less stable in the Na+ electrolyte, the formation of surface oxides from Pt-OH happens at lower potential than in the LiOH solution, resulting in fast changes of both the maximum potential and oscillation frequency and short time-series, i.e., the drift becoming higher. Finally, the conversion of Pt-OH onto Pt oxides is still easier in KOH solutions, producing short time-series and does not allow the oscillatory behavior. (AU)

• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 16/14758-0 - Instabilities in electrocatalysis: complex kinetics catalyzed by model PT surfaces
• Grantee: Kaline Nascimento da Silva
• Support Opportunities: Scholarships in Brazil - Master