Research on methanol-tolerant catalysts for the oxygen reduction reaction

M. ASTEAZARAN; G. CESPEDES; S. BENGIÓ; M.S. MORENO; W.E. TRIACA; A.M. CASTRO LUNA

JOURNAL OF APPLIED ELECTROCHEMISTRY

SPRINGER

Lugar: Berlin; Año: 2015 vol. 45 p. 1187 - 1193

0021-891X

Direct methanol fuel cells (DMFCs) generateelectricity in a clean and efficient way, so they are avaluable alternative to traditional environmentally harmfultechnologies. Portable power sources are one of the applicationsof passive DMFCs. One of the requirements inthese devices is the use of high alcohol concentration.Methanol permeation across the polymer electrolytemembrane (methanol crossover) causes a loss of fuel cellefficiency as the oxygen reduction reaction (ORR) and themethanol oxidation reaction (MOR) occur simultaneouslyat the cathode. To develop methanol-tolerant catalysts withsuitable activity, different PtM/C and PtMRu/C combinationswith M = Co or Fe were prepared by a modifiedimpregnation method. The synthesized catalysts werestudied to determine the role of the components in enhancingthe ORR and simultaneously discouraging theMOR. The materials were characterized by TEM, XPS andEDS. Well-distributed particles for all the catalysts wereshown by TEM. XPS spectra revealed that the methodproduces a great amount of metallic Pt. The electrochemicalcharacterization was carried out by linear sweepvoltammetry and cyclic voltammetry, in a three-electrodeelectrochemical cell with a glassy carbon rotating diskelectrode covered with a thin catalytic layer and a Nafionfilm as the working electrode. Binary and ternary catalystshave a good activity for the ORR. However, the enhancedactivity of binary catalysts is lost when the ORR is studiedin the presence of methanol. Ternary catalysts containingRu showed higher methanol-tolerance, regardless of thecomposition.