Formation of Cu@Pd core@shell nanocatalysts with high activity for ethanol electro-oxidation in alkaline medium
2020; Elsevier BV; Volume: 538; Linguagem: Inglês
10.1016/j.apsusc.2020.148119
ISSN1873-5584
AutoresJ. Maya-Cornejo, Jesús Adrián Díaz‐Real, J. Luis López‐Miranda, Lorena Álvarez‒Contreras, Rodrigo Esparza, Noé Arjona, Miriam Estévez,
Tópico(s)Catalytic Processes in Materials Science
ResumoIn this work, the formation of Cu@Pd core–shell nanoparticles was studied by optimizing the reduction of Cu2+ to Cu0 used as cores, and by increasing the amount of Pd precursor, labelling these materials as Cu@Pd I to IV, respectively. X-ray diffraction, UV–vis tests, and X-ray photoelectron spectroscopy (XPS) revealed the formation and progressive growth of Cu@Pd nanoparticles with the increase of the Pd content. High-resolution transmission electron microscopy (HR-TEM) and line-scan energy-dispersive spectroscopy (EDX line-scan) tests indicated that the Cu@Pd IV was the sample that displayed a better formation of a core@shell structure, having an average particle size of 5.9 nm. Electrochemical tests were performed using a synthesized Pd/C nanomaterial (15.7 nm) as reference electrocatalyst for the ethanol oxidation reaction (EOR), and the effect of the fuel and electrolyte concentrations were analyzed. The highest activity was obtained with 3 M ethanol + 2 M KOH, where Cu@Pd IV displayed an onset potential (Eonset) of −0.6 V vs. NHE and an oxidation peak potential (Ep) of 0.11 V. This Ep was 400 mV lower to that achieved by Pd/C at the same conditions. In addition, Cu@Pd IV presented the highest current density (6.78 mA cm−2, 1.6 times higher than Pd/C).
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