Template Synthesis And Electric Catalytic Performance Research Of Mesoporous Carbon

Due to its particular structure, ordered mesoporous carbon can be used as good Pt-loaded catalyst in electric catalytic field with great application value. The hard template method is the most mature synthesis method for preparation of mesoporous carbon, but the synthesis progress is often complexed for this method including synthesis of silicon source, causing the waste of time and cost. Therefore, people hope can directly use cheap natural raw mesoporous materials to participate the synthesis, on the basis of retaining the original specific structure, so as to solve the above problem.In this paper, we introduced the diatomite to preparation process, and ordered mesoporous carbon was synthesized using phenolic resin (resol) as precursor, with different template agents, through the evaporation self-assembly method. Keeping the proportion of resol changeless, we studied the influence on the structure of the mesoporous carbon with different preparation conditions and discussed the function of diatomite in synthesis. Then, using ordered mesoporous carbon as supporters, Pt-loaded catalysts were synthesized through the microwave method, and their electric catalytic activities were studied in the methanol system.Ordered mesoporous carbon has been successfully synthesized with F127 as template agent, and the result shows that ordered mesoporous carbon could be prepared under the synthetic temperature between 110℃ and 130℃, with the ratio of F127 and resol between 0.5～1, with the ratio of diatomite and resol between 0.5～1. Under the above conditions, the mesoporous carbons have larger pore sizes and higher specific surface area than the sample prepared without diatomite, with the maximum values as 11.3 nm and 773m2/g, respectively. The diatomite could produce outward traction and prevent the shrinkage of the mesoporous carbon during the high temperature calcining process, which increased the aperture and specific surface area of the mesoporous carbon.Using P123 instead of F127, ordered mesoporous carbon was also prepared. Experiments indicated that the ordered degree of mesoporous carbon was the best when the proportion of diatomite and resol was 0.5, the ratio of P123 and resol was 0.5, and carbonization temperature was 600℃. Diatomite could effectively prevent structure deformation, thus ordered mesoporous carbon could be synthesized with P123 as template agent without the alkaline conditions. Its aperture was 7.3nm, and specific surface area was 773m2/g.The diatomite, after aluminizing, could also participate in the preparation of ordered mesoporous carbon. When the ratio of diatomite and resol was 0.25, with the aluminizing diatomite to participate in the preparation of sample, the ordered degree of the mesoporous carbon was higher than those using pure diatomite. Compared to the sample with P123, the aperture of the sample with F127 as template agent was larger, and its ordered degree was also higher. Under these synthetic conditions, the pore diameter and specific surface area of the mesoporous carbon was 8.9 nm and 651m2/g. Small parts of the mesoporous carbon made copies of the holes in the wall of diatom shell, and it generated a lot of carbon membrane structure.The above ordered mesoporous carbon was used to load Pt catalyst. The results of electrochemistry circle volt-ampere tests show that the usage of pure diatomaceous earth could improve the electric catalytic performance of samples. When the ratio of diatomite and resol was 0.5, the sample had the highest catalytic activity. The samples had enhanced catalytic properties, when they were synthesized with F127 instead of P123. Aluminized diatomites could improve the ordered degree of samples, whereas these samples showed no catalytic activity.