Study of Pt/C nanoparticles modified with Sn, Ru and Ta for direct alcohol fuel cells
Name: MARIA APARECIDA RIBEIRO QUEIROZ
Type: PhD thesis
Publication date: 23/04/2020
Advisor:
Name |
Role |
|---|---|
| JOSIMAR RIBEIRO | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ADILSON RIBEIRO PRADO | External Examiner * |
| JOSIMAR RIBEIRO | Advisor * |
| JUSSARA FARIAS FARDIN | External Examiner * |
| MARCOS ANTONIO RIBEIRO | Internal Examiner * |
| RAFAEL DE QUEIROZ FERREIRA | Internal Examiner * |
Summary: In this work, the influence of the addition of Sn, Ru and/or Ta on the electrocatalytic activity of Pt/C electrocatalysts, synthesized by the thermal decomposition method of polymeric precursors, was studied. Chemical-physical characterization, the measurements of ATG provide calcination temperature, 350 °C; with DRX obtained an increase in the parameter the CFC Pt structure due to the incorporation of Sn and Ta metals, the nanoparticles presented crystallite size between 3.8 and 9.8 nm with homogeneous distribution in the support. In the electrochemical characterization, the volume of 20 µL of electrocatalytic material was defined to be added on the surface of the working electrode, since the increase in volume was not related to ECSA. A relationship was observed between the increases in the proportion of Pt: Sn with the increase in ECSA and the electrocatalytic activity of the electrocatalysts, WHERE a 9:1 ratio presented the best results. In the stability test with 1000 cycles and CO-Stripping experiments the electrocatalyst, Pt9Sn1Ru1Ta1/C had the least area loss, 29%, until the end of 1000 cycles and was electrocatalyst with higher ECSA value, 39.4 m2 gPt-1. Results of cyclic voltammetry in alcohols the cited electrocatalyst showed the highest current values for all alcohols with the highest value being, 764 A gPt-1, for methanol and the lowest, 95 A gPt-1, for glycerol. From the results of the chronoamperometry and chronopotentiometry, it was observed that the Pt7Sn1Ta2/C electrocatalyst had the smallest current and potential variation, being the electrocatalyst with greater capacity to renew the electrocatalytic surface and less susceptible to poisoning, mainly for methanol, being the most indicated for the electro-oxidation of this alcohol. For the other alcohols, ethanol, ethylene glycol, and glycerol, the results showed that the addition of Sn, Ru, and Ta in nanoparticles of Pt/C, increase in electrocatalytic activity in the electro-oxidation of these alcohols. Where the Pt9Sn1Ru1Ta1/C electrocatalyst shows the best results that can be considered an alternative for use in direct alcohol fuel.
