abstract
Platinum-ruthenium alloy electrocatalysts, for methanol oxidation reaction, were prepared on carbons thermally treated in helium atmosphere or chemically functionalized in H2O2, or in HNO3 + H2SO4 or in HNO3 solutions. The functionalized carbon that is produced using acid solutions contains more surface oxygenated functional groups than carbon treated with H2O2 solution or HeTT. The XRD/HR-TEM analysis have showed the existence of a higher alloying degree for Pt-Ru electrocatalysts supported on functionalized carbon, which present superior electrocatalytic performance, assessed by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy, as compared to electrocatalysts on unfunctionalized carbon. It also was found that Pt-Ru alloy electrocatalysts on functionalized carbon improve the reaction rate compared to Pt-Ru on carbons treated with H2O2 solution and thermally. A mechanism is discussed, where oxygenated groups generated from acid functionalization of carbon and adsorbed on Pt-Ru electrocatalysts are considered to enhance the electrocatalytic activity of the methanol oxidation reaction. (C) 2011 Elsevier Ltd. All rights reserved.
keywords
ORDERED MESOPOROUS CARBON; FUEL-CELL APPLICATIONS; PLATINUM CATALYSTS; PARTICLE-SIZE; XRD ANALYSIS; ELECTROOXIDATION; ALLOYS; IMPEDANCE; BLACK; ANODE
subject category
Electrochemistry
authors
Salgado, JRC; Fernandes, JCS; do Rego, AMB; Ferraria, AM; Duarte, RG; Ferreira, MGS
our authors
Mário Guerreiro Silva Ferreira
Retired Professoracknowledgements
The authors acknowledge Dr. Andrei Salak (Universidade de Aveiro) for performing the XRD measurements and Dr. A.P.S. Dias (ICEMS/IST) for the useful discussions. J.R.C. Salgado acknowledges the financial support of Portuguese Foundation for Science and Technology (FCT, Ciencia 2008). Thanks are also due to the Synchrotron Light Brazilian Laboratory (LNLS, Campinas, SP, Brazil) for assisting with the HR-TEM experiments.