The Role of Surface Functionalities in PtGe and PtIn Catalysts for Direct Methanol Fuel Cells

VEIZAGA, NATALIA S.; DE MIGUEL, SERGIO R.; BRUNO, MARIANO; RODRIGUEZ, VIRGINIA I.

Electrocatalysis

Springer

Año: 2019 p. 125 - 133

1868-2529

Bimetallic PtGe and PtIn catalysts were prepared over Vulcan carbon (VC) and multiwall carbon nanotubes (NT) by conventionalimpregnation method (CI). These supports were functionalized with citric or nitric acid. The structural and electrochemicalcharacteristics of the different functionalized supported catalysts were analyzed in order to determine the influence of thefunctional groups. The methods applied were temperature programmed reduction (TPR), X-ray photoelectron spectroscopy(XPS), cyclohexane dehydrogenation reaction (CHD), and CO stripping. The functionalization treatment with citric or nitricacid eases CO oxidation to CO2, decreasing poisoning effect of CO over Pt, due to the development of oxygenated groups onsupport surfaces and in the nearby Ge and In. Bimetallic catalysts supported on carbons functionalized with HNO3 presentincreasing electrochemical active surface values, indicating a better electrochemical behavior than the corresponding monometalliccatalysts. DMFC experiments show a very good behavior of PtGe catalysts, mainly for those supported on HNO3-functionalizedNT, reaching a maximum power density of 80 mW cm−2. Conversely, PtIn catalysts exhibit a very poor behavior.