Modification And Properties Of Ordered Mesoporous Carbon As Pt Catalyst Support

Ordered mesoporous carbon-silica composites have been synthesized from a direct tri-constituent co-assembly with resol as carbon precursor, tetraethyl orthosilicate (TEOS) as silica precursor, F127 as the structure directing agent and nickel chloride as a catalyst for the hydrolysis of TEOS in this paper. Ordered meosoporous carbon was obtained after etched by the HF. The C-Ni(15) exhibits the best structural properties, which the BET surface area, total pore volume, and pore diameter of the mesoporous carbon reaches to 1220.2 m2/g, 1.13 cm3/g, and 5.1 nm, respectively. Pt nanoparticles supported on the mesoporous carbon were fabricated by a facile microwave synthesis process. The results show that the catalyst Pt/C-Ni(15) has excellent electrochemical performance for hydrogen electro-oxidation. The electrochemical active surface reaches a peak value of 78.5 m2/g.Ordered mesoporous carbon with 2D hexagonal structure was also successfully synthesized in one-step without TEOS. It has been proved that the obtained carbon was hydrophobic, so few amount of nickel chloride was added during the synthesis process to improve the wettability. By comparison, two methods were used to load Pt nanoparticles on the meosoporous carbon. It was efficient to loading Pt nanoparticles on the poor hydrophilic C-0 by solid state synthesis method. But the electrocatalytic activity of Pt nanoparticle wasn't enhanced with the addition of the nickel chloride. The higher dispersion and larger number of the Pt nanoparticles was obtained by microwave synthesis process with the addition of the nickel chloride. The electrocatalytic activity of Pt-C-5-MW for adsorbed hydrogen reaches to 107.8 m2/g.According to the previous study, some oxides existed in the meosoporous carbon may be favorable for the improvement of the electrocatalysis. The carbon-silica composites were fabricated by adding few mount of TEOS to the process of the synthesis of the mesoporous carbon in one-step combining the advantages of the direct tri-constituent co-assembly method and the one-step method. The catalyst using carbon-silica composites CS-(x) as support has excellent electrochemical performance for hydrogen. The electrochemical active surface of Pt particles for the Pt/CS-(0.5) in sulfuric acid solution reaches a peak value of 63.9 m2/g. This value is comparable with that of the catalyst loading on the tri-constituent co-assembly carbon. Because of the simplification of the synthesis procedure, the carbon-silica composites could have great potential applications.