N-Doped Mesoporous Carbon from Melamine-Modified Resorcinol-Formaldehyde Polymer Resin as Catalytic Support for Electrochemical Investigation of Formic acid Oxidation Reaction

Nitrogen-doped mesoporous carbon (N-MC) was prepared by pyrolysis of melamine-modified resorcinol-formaldehyde (RF) resin in different melamine molar ratios under N 2 atmosphere at 900 °C. The resulting N-MC materials were used as a support of Pd nanoparticles (Pd/N-MC) and evaluated as catalyst for a formic acid electro-oxidation reaction (FAOR) by cyclic voltammetry. The physical-chemical characteristics of the N-MCs were evaluated by FTIR, XRD, SAXS, Raman, and BET techniques. The N-MC obtained from resins with higher melamine concentration resulted in carbon structure with higher graphitic crystallinity and morphology with deformed pores caused by inefficient self-assembly; furthermore, the N content, determined by elemental analysis, ranged from 1.2 to 3.3%. For Pd/N-MC catalysts, the TEM analysis showed better dispersion and narrow size distribution of Pd nanoparticles for the catalysts supported on N-MC, being the smallest for Pd/MC10. The electrochemical evaluation confirmed that the catalysts supported in N-MC with open-cylindrical pores and high N content exhibited higher electrochemical surface area (ECSA). In addition, the catalytic activity towards FAOR indicated higher current densities at lower potential values than Pd/MC. This study demonstrates that in-situ Nitrogen doping is a convenient methodology to obtain N carbon materials with well-tailored pores that promote better dispersion of metal nanoparticles, and support-catalyst interaction resulting in enhanced electrochemical properties.