Methanol Oxidation in Alkaline Medium Using PtIn/C Electrocatalysts

• Main Author: Santos, M. C. L.
• Publication Date: 2016
• Other Authors: Ottoni, C. A. [UNESP], Souza, R. F. B. de, Silva, S. G. da, Assumpcao, M. H. M. T., Spinace, E. V., Neto, A. O.
• Format: Article
• Language: eng
• Source: Repositório Institucional da UNESP
• Download full: http://dx.doi.org/10.1007/s12678-016-0324-z; http://hdl.handle.net/11449/162107
• topic: Methanol oxidation; PtIn electrocatalysts; Alkaline fuel cell

Pt/C and PtIn/C with atomic ratios of 90:10, 70:30, and 50:50 were investigated for methanol electro-oxidation in alkaline media by using cyclic voltammetry (CV), chronoamperometry (CA), and direct methanol alkaline fuel cell (DMAFC). All electrocatalysts were synthesized using sodium borohydride method with 20 wt% of metals loading on carbon. X-ray diffraction (XRD) analysis revealed that bimetallic PtIn had faced centered cubic structure and, also, confirmed alloy formation for PtIn/C nanoparticles. Transmission electron micrographs showed metal nanoparticles with average particle size between 3.0 and 5.0 nm; however, the particle size increases when the In content was increased in PtIn/C. In the CV experiments, the onset potential of methanol electro-oxidation shifted to lower values as the indium content increased. Chronoamperometry experiments and direct methanol alkaline fuel cell suggested PtIn/C (70:30) as the most promising material for methanol electro-oxidation: this result could be explained by the presence of Pt and In in close contact (electronic effect) as the occurrence of oxy-hydroxy interactions.