CMK-5 mesoporous carbon synthesized via chemical vapor deposition of ferrocene as catalyst support for methanol oxidation

A novel and effective method was described in this work to prepare two-dimensional hexagonally ordered mesoporous CMK-5 carbon materials. This method is based on the chemical vapor deposition (CVD) of ferrocene in the mesopores of SBA-15 at 500 degrees C, followed by graphitization at different temperatures. Both the silica/carbon composite and the resulting CMK-5 were characterized by N-2 adsorption, powder X-ray diffraction, Raman spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy (HRTEM), and thermogravimetric analysis. It was found that the ferrocene could be used as a new precursor to prepare CMK-5 nanopipes, with pipe thicknesses varying from 0.8 to 2.6 nm, by increasing the CVD time from 20 to 120 min. The resulting CMK-5 exhibits high Brunauer-Emmett-Teller (BET) surface area (1044-2449 m(2)/g) and large pore volume (1.13-2.20 cm(3)/g). The graphitization degree of the resulting CMK-5 was investigated by pyrolyzing the corresponding silica/carbon composite at different temperatures. Pyrolysis temperatures below 850 degrees C led to gradually improved graphitization degrees of CMK-5 nanopipes. Pyrolysis temperatures above 850 degrees C resulted in the partial collapse of ordered CMK-5 nanopipes accompanied by the appearance of a considerable amount of entangled graphitic ribbons. The structural evolution process of CMK-5 from ordered nanopipes to the final entangled graphitic ribbons was observed by HRTEM. The obtained CMK-5 was applied as a catalyst support of Pt for methanol oxidation. The electrochemical activities of Pt nanoparticles loaded on the CMK-5 carbon materials were investigated by cyclic voltammograms and compared with the commercial Pt/Vulcan XC-72 catalyst. It was found that the specific mass activity of Pt/CMK-5 was much higher than Pt/Vulcan XC-72.