Nitrogen Doped and Functionalized Carbon Materials as Supports for Catalysts in Electro-Oxidation of Methanol

Abstract

The objective of this work is to study the behavior of Nitrogen-doped carbons as supports of catalysts for the electro-oxidation of methanol. Two carbon materials have been considered: a) carbon xerogels (CXG), highly mesoporous, whose porosity and pore size distribution are easily performed during the synthesis method; b) carbon nanofibers (CNF), which have a high electrical conductivity, good behavior in high temperature conditions and resistance to acid/basic media. Meanwhile, a commercial carbon black (Vulcan XC72R) which is commonly used in manufacturing of electrocatalysts fuel cells was used for comparison. Nitrogen was introduced into the CXG during the synthesis process, what is commonly referred as doping, by including melamine as a reactant. In contrast, N-groups were created over CNF by post-treatment with: ammonia (25%), urea (98%), melamine (99%) and ethylenediamine (99.5%), with a carbon: nitrogen molar ratio 1:0.6. N-containing carbon materials were characterized by elemental analysis, nitrogen adsorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), SEM-EDX and TEM to determinate the amount and forms of nitrogen introduced. Pt-catalysts were prepared by the microemulsion method. The influence of the nitrogen doping and functionalization on the catalytic behavior in the electrochemical oxidation of methanol was evaluated by different physicochemical and electrochemical analysis.