Electrocatalysis of oxygen reduction when varying the mass ratio of metal nanoparticles to carbon support for catalysts with a 10 to 10 to 80 mol% of Pt and Pd on Ag
Por:
Pech-Pech, I. E., Gervasio, Dominic, Aguila, S. A., Perez-Robles, J. F.
Publicada:
9 ago 2018
Ahead of Print:
1 ene 2018
Resumen:
The reduction of total Pt-loading in a cathode catalyst without sacrificing performance is one of the key objectives for the large-scale commercialization of proton exchange membrane fuel cell (PEMFC) technology. A core-shell type nanostructured catalyst with a Pt-loading 20 times lower than a commercial catalyst is demonstrated herein to be more active for the electrocatalysis of the oxygen reduction reaction (ORR) in acid electrolyte. The weight ratio of metal nanoparticles on carbon support is the key to achieving the highest ORR activity in a series of silver-based catalysts, all with 10 mol percent of Pt and 10 mol percent of Pd over 80 mol percent of silver (Ag) and supported on untreated Vulcan carbon to form an electrocatalyst (Ag@Pt10Pd10/C) with either 5, 10, 20 or 30 wt% of total metals on carbon; which correspond to a Pt concentration around 1, 2, 3 and 5 wt%, respectively. All metal nanostructures on carbon show a similar morphology, size and structure. Thin films of these four Ag@Pt10Pd10/C catalysts on rotating disk electrodes (TF-RDEs) all shown a 4-electrons pathway for the ORR and give higher exchange current densities (jo > 3.8 mA/cm2) than a commercial Etek Pt20/C catalyst (jo = 2.4 mA/cm2). The Ag@Pt10Pd10/C catalyst with 5 wt% of total metals (1 wt% of Pt) on carbon gives the best electrocatalysis; reducing molecular oxygen to water two times faster and generating 25% higher current per milligram of platinum (mass activity) than the commercial catalyst (Pt20/C). Therefore, the Ag@Pt10Pd10/C catalyst with 5 wt% of total metals is a new catalyst for ORR for a PEMFC with a lower Pt loading and cost. © 2018 Hydrogen Energy Publications LLC
Filiaciones:
Pech-Pech, I. E.:
Dept. of Materials, CINVESTAV-IPN, Libramiento Norponiente 2000 Fracc. Real de Juriquilla, Querétaro, Qro., Mexico
Center of Nanoscience and Nanotechnology, UNAM, Km. 107 Carretera Tijuana-Ensenada, Ensenada, Baja California, Mexico
IPN, CINVESTAV, Dept Mat, Libramiento Norponiente 2000 Fracc Real, Queretaro 76230, Qro, Mexico
UNAM, Ctr Nanosci & Nanotechnol, Km 107 Carretera Tijuana Ensenada, Ensenada 22860, Baja California, Mexico
Gervasio, Dominic:
Dept. of Chemical & Environmental Engineering, University of Arizona, 1133 E. James E. Rogers Way #108, Tucson, AZ, United States
Univ Arizona, Dept Chem & Environm Engn, 1133 E James E Rogers Way 108, Tucson, AZ 85721 USA
Aguila, S. A.:
Center of Nanoscience and Nanotechnology, UNAM, Km. 107 Carretera Tijuana-Ensenada, Ensenada, Baja California, Mexico
UNAM, Ctr Nanosci & Nanotechnol, Km 107 Carretera Tijuana Ensenada, Ensenada 22860, Baja California, Mexico
Perez-Robles, J. F.:
Dept. of Materials, CINVESTAV-IPN, Libramiento Norponiente 2000 Fracc. Real de Juriquilla, Querétaro, Qro., Mexico
IPN, CINVESTAV, Dept Mat, Libramiento Norponiente 2000 Fracc Real, Queretaro 76230, Qro, Mexico
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