RESEARCH ARTICLE Sn@Pt and Rh@Pt core–shell nanoparticles synthesis for glycerol oxidation Marilia M. S. Pupo • Franz E. Lo ´pez-Sua ´rez • Agustı ´n Bueno-Lo ´pez • Cristiano T. Meneses • Katlin I. B. Eguiluz • Giancarlo R. Salazar-Banda Received: 26 June 2014 / Accepted: 22 September 2014 / Published online: 28 September 2014 Ó Springer Science+Business Media Dordrecht 2014 Abstract The development and optimization of electro- catalysts for application in fuel cell systems have been the focus of a variety of studies where core–shell structures have been considered as a promising alternative among the materials studied. We synthesized core–shell nanoparticles of Sn x @Pt y and Rh x @Pt y (Sn@Pt, Sn@Pt 2 , Sn@Pt 3 , Rh@Pt, Rh@Pt 2 , and Rh@Pt 3 ) through a reduction meth- odology using sodium borohydride. These nanoparticles were electrochemically characterized by cyclic voltam- metry and further analyzed by cyclic voltammetry studying their catalytic activity toward glycerol electro-oxidation; chronoamperometry and potentiostatic polarization exper- iments were also carried out. The physical characterization was carried out by X-ray diffraction, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The onset potential for glycerol oxidation was shifted in 130 and 120 mV on the Sn@Pt 3 /C and Rh@Pt 3 /C catalysts, respectively, compared to commercial Pt/C, while the stationary pseudo-current density, taken at 600 mV, increased 2-fold and 5-fold for these catalysts related to Pt/C, respectively. Thus, the cat- alysts synthesized by the developed methodology have enhanced catalytic activity toward the electro-oxidation of glycerol, representing an interesting alternative for fuel cell systems. Keywords Core–shell  Glycerol oxidation  Electrocatalysis  Fuel cells 1 Introduction The increase in glycerol production, the main co-product of biodiesel production, turns glycerol’s final destination into a serious problem to be solved by the biodiesel industry. Although there are many pharmaceutical applications, its growing production is beginning to show clear signs of exceeding the demand. Therefore, alternative applications for glycerol need to be considered. Considering glycerol’s attributes, one of its most promising applications is as an energy source in fuel cell systems. Fuel cells are electrochemical devices that convert chemical energy into electric current by the chemical reaction of a fuel and an oxidant [1]. Due to their sim- plicity, lightness, and operation at low temperatures, they are seen as alternative energetic routes of great viability and outcomes. Many reports have studied direct oxidation fuel cells fueled by methanol, ethanol, and ethylene glycol [2–6], but few studies are concerned with fuel cells using glycerol. The hindrance to extract the energy available in an alcohol is mostly caused by parallel reactions, mainly due to the poor ability of metallic surfaces to promote the cleavage of C–C bonds. However, the oxidation pathways for diverse alcohols are different. For instance, in acid media, for ethanol oxidation, CO 2 is produced from CO in M. M. S. Pupo  F. E. Lo ´pez-Sua ´rez  K. I. B. Eguiluz  G. R. Salazar-Banda (&) Laborato ´rio de Eletroquı ´mica e Nanotecnologia, Instituto de Tecnologia e Pesquisa/Programa de Po ´s-graduac ¸a ˜o em Engenharia de Processos, Universidade Tiradentes, Aracaju, Sergipe 49.032-490, Brazil e-mail: gianrsb@gmail.com A. Bueno-Lo ´pez MCMA Group, Department of Inorganic Chemistry, Faculty of Sciences, University of Alicante, Ap. 99, E-03080, Alicante, Spain C. T. Meneses Departamento de Fı ´sica, Universidade Federal de Sergipe, Campus Itabaiana, Itabaiana, Sergipe 49.500-000, Brazil 123 J Appl Electrochem (2015) 45:139–150 DOI 10.1007/s10800-014-0757-0