Functionalized mesoporous carbons as platinum electrocatalyst supports for applications in fuel cells

Mesoporous carbons (MCs) were synthesized by an organic-organic self-assembly process and surface-modified by the conventional acid-oxidation, H₂O₂ oxidation and 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane (AEPTMS) grafted methods. Fabrication of Pt nanoparticles (NPs) supported on MC (Pt/MC) and modified MC (Pt/MC-HNO₃, Pt/MC-H₂O₂ and Pt/MC-AEPTMS) were further performed. These resultant catalysts were characterized by a variety of different spectroscopic and analytical techniques such as Fourier transformation infrared spectroscopy (FTIR), X-ray diffraction (XRD), and transmission electron microscopy (TEM) analysis. Pt NPs were found to be aggregated on the Pt/MC-HNO₃ catalysts. For Pt/MC-AEPTMS catalysts, Pt NPs (ca. 2 nm) supported uniformly on surface of modified MC which however has a low electrical conductivity. Among three surface-modified methods, the H₂O₂ treatment method was a simply controllable way for surface modification of MC which possesses desirable electrical conductivity, well-dispersed and nanosized Pt (ca. 3 nm). The Pt/MC-H₂O₂ samples were found to have superior electrocatalytic activity for oxygen reduction reaction in comparison with synthesized Pt/MC, Pt/MC-HNO₃, Pt/MC-AEPTMS and the typical commercial electrocatalyst (Pt/XC-72).