Synthesis of ordered mesoporous carbon doped with carbon nanotubes and a new strategy to use it as a support for Pt electrocatalysts

Abstract

Our work pivots around modified mesoporous materials as supports for Pt electrocatalysts. Carbon nanotubes–ordered mesoporous carbon (CNTs–OMC) composite materials have been successfully fabricated through a hard template method. Firstly, carbon nanotubes–ordered mesoporous silica (CNTs–OMS) composites were prepared by using P123 as an organic template for directing the formation of mesoporous silica. Ordered mesoporous carbon doped with CNTs (designated as CNTs–OMC) has been successfully replicated from the above-synthesized CNTs–OMS template by using sucrose as a carbon precursor. We find that the addition of appropriate CNTs has no effect on the ordered mesoporous structure of carbon and can make the mesoporous structure more stable. The TEM images of the CNTs–OMC show highly ordered parallel channels and CNTs can be uniformly embedded in the ordered mesoporous carbon matrix. The OMC after doping shows a higher electrical conductivity of 26.4 S m−1 while that of the OMC (before doping) is only 4.3 S m−1, which is due to the nature of its graphitic framework as well as its lower interfacial resistance. Then the CNTs–OMC and OMCs were used as fuel cell catalyst supports for loading Pt nanoparticles prepared via a microwave synthesis process. The conductivity and plumbaginous degree of the CNTs–OMC composite are higher than those of OMC, which is beneficial for loading Pt nanoparticles. The Pt/CNTs–OMC catalyst has a higher electrochemical active surface area of 113.4 m2 g−1 than that of the Pt/OMC catalyst, which indicates that the addition of an appropriate amount of CNTs to OMC significantly improves the performance of Pt nanoparticles.