Solvent effect in the synthesis of nanostructured Pt–Sn/CNT as electrocatalysts for the electrooxidation of ethanol

• Published in: International journal of hydrogen energy 2019-05, Vol.44 (24), p.12430-12438
• Main Authors: Romero-Cano, Luis A., Rosado-Ortiz, G., Valenzuela-Muñiz, A.M., Ordóñez, L.C., Gauvin, R., Verde Gómez, Y.
• Format: Article
• Language: English
• Subjects: Carbon nanotubes; Colloidal dispersion; Electrooxidation of ethanol; Pt–Sn nanoparticles
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2018.09.087

Pt and Pt–Sn nanoparticles were synthesized and supported onto carbon nanotubes (CNT), the electrocatalytic activity towards the ethanol oxidation reaction was analyzed. The effect of the solvent employed for the synthesis was evaluated. Metal nanoparticles synthesis was made using water (Pt–Sn/CNT-W) or ethanol (Pt–Sn/CNT-E) as a solvent. Pt–Sn/CNT-W material presented only Pt–Sn alloy nanoparticles homogeneously distributed on the carbon nanotubes support. Pt–Sn/CNT-E sample showed non well-dispersed nanoparticles forming agglomerates along the CNTs surface with predominantly Sn4+ superficial species (SnO2) as show the XPS, FTIR and electrochemical results. These surface arrangements had important effects on the electrocatalytic properties. Pt–Sn/CNT-W shows higher ethanol electrooxidation activity than the Pt–Sn/CNT-E, which is attributed to: a) the double catalytic effect and the intrinsic electronic mechanism favored by the presence of Sn; b) the good particle dispersion of the bimetallic active phase on the CNT and; c) the absence of SnO2 species. [Display omitted] •Ethanol as solvent in the colloidal method favors the synthesis of SnO2 agglomerated.•Water as solvent in the colloidal method favors Pt–Sn alloy nanoparticles.•Bimetallic catalysts showed higher electroactivity compared to the monometallic.