Electrochemical Oxidation of the Carbon Support to Synthesize Pt(Cu) and Pt-Ru(Cu) Core-Shell Electrocatalysts for Low-Temperature Fuel Cells

Catalysts

Griselda Caballero-Manrique²  Enric Brillas²  Francesc Centellas²  José Antonio Garrido²  Rosa Mar໚ Rodríguez²  Pere-Lluís Cabot¹ 

[1]Laboratori d’Electroquímica dels Materials i del Medi Ambient, Departament de Química Física, Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain

关键词: electrochemical oxidation of carbon;    core-shell Pt(Cu) nanoparticles;    core-shell Pt-Ru(Cu)nanoparticles;    Pt deposition by galvanic exchange;    Ru spontaneous deposition;    hydrogen adsorption/desorption;    CO oxidation;    XPS;    HRTEM;   

DOI  :  10.3390/catal5020815

来源: mdpi

【 摘 要 】

The synthesis of core-shell Pt(Cu) and Pt-Ru(Cu) electrocatalysts allows for a reduction in the amount of precious metal and, as was previously shown, a better CO oxidation performance can be achieved when compared to the nanoparticulated Pt and Pt-Ru ones. In this paper, the carbon black used as the support was previously submitted to electrochemical oxidation and characterized by XPS. The new catalysts thus prepared were characterized by HRTEM, FFT, EDX, and electrochemical techniques. Cu nanoparticles were generated by electrodeposition and were further transformed into Pt(Cu) and Pt-Ru(Cu) core-shell nanoparticles by successive galvanic exchange with Pt and spontaneous deposition of Ru species, the smallest ones being 3.3 nm in mean size. The onset potential for CO oxidation was as good as that obtained for the untreated carbon, with CO stripping peak potentials about 0.1 and 0.2 V more negative than those corresponding to Pt/C and Ru-decorated Pt/C, respectively. Carbon oxidation yielded an additional improvement in the catalyst performance, because the ECSA values for hydrogen adsorption/desorption were much higher than those obtained for the non-oxidized carbon. This suggested a higher accessibility of the Pt sites in spite of having the same nanoparticle structure and mean size.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.