Publicación: Cu and Pd nanoparticles supported on a graphitic carbon material as bifunctional HER/ORR electrocatalysts
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2020-11-01
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info:eu-repo/semantics/openAccess
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Resumen
The development of efficient, available and robust substitutes for the Pt-based electrocatalysts is very important for a sustainable energetic future. Herein, we report a series of composites based on Cu, Pd and Cu-Pd nanoparticles (NPs) supported on high surface area graphite (HSAG), as electrocatalysts for the energy-related reduction reactions – oxygen reduction (ORR) and hydrogen evolution (HER) reactions. All the composites showed interesting ORR electrocatalytic activities in alkaline medium. The Pd/HSAG and Cu-Pd/HSAG composites exhibited the most promising performances, with onset potentials of 0.84 and 0.91 V and current densities of jL, 0.3 V, 1600 rpm=−3.5 and −4.2 mA cm−2, respectively. All the composites showed selectivity for the 4-electron process and Tafel slopes in the range 48–77 mV dec−1. The metal/HSAG composites
revealed a great tolerance to methanol and moderate electrochemical stability. In highly acidic medium (0.5 mol dm−3 H2SO4, pH=0.3) only the Cu-Pd/HSAG and Pd/HSAG electrocatalysts
presented electrocatalytic activity toward HER, with relative low overpotentials (η10=0.145 and 0.063 V, respectively), small Tafel slopes (75 and 42 mV dec−1) and similar exchange current densities (0.43 and
0.57 mA cm−2). These electrocatalysts also showed moderate electrochemical stability, in particular Cu-Pd/ HSAG for which overpotential only changed between 0.033 and 0.038 V for j=40mAcm−2.
The results showed that only small loading of Pd NPs (1 wt.% Pd) was able to improve significantly the ORR/ HER electrocatalytic activity, which is a very important outcome to rationalize the design of efficient and costeffective electrocatalysts in future.
Descripción
The registered version of this article, first published in “Catalysis Today, Volume 357", is available online at the publisher's website: Elsevier, https://doi.org/10.1016/j.cattod.2019.04.043
La versión registrada de este artículo, publicado por primera vez en “Catalysis Today, Volume 357", está disponible en línea en el sitio web del editor: Elsevier, https://doi.org/10.1016/j.cattod.2019.04.043
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Palabras clave
Oxygen reduction reaction, Hydrogen evolution reaction, Palladium nanoparticles, Copper nanoparticles, Bifunctionality
Citación
Marta Nunes, Diana M. Fernandes, M.V. Morales, I. Rodríguez-Ramos, A. Guerrero-Ruiz, Cristina Freire, Cu and Pd nanoparticles supported on a graphitic carbon material as bifunctional HER/ORR electrocatalysts, Catalysis Today, Volume 357, 2020, Pages 279-290, ISSN 0920-5861, https://doi.org/10.1016/j.cattod.2019.04.043
Centro
Facultades y escuelas::Facultad de Ciencias
Departamento
Química Inorgánica y Química Técnica