Methanol oxidation on platinum-ruthenium nanoparticles supported on well defined mesoporous carbons

A mesoporous carbon structure was template-synthesized from silica nanoparticles with internal M41S type mesopores. The silica template was synthesized according to Suzuki et al. using an ionic surfactant to create the internal mesopores 1.8-3.5 nm diameter and a non-ionic surfactant to limit the overall size of the particle. Larger mesopores in the silica are needed for carbonization to a better structure. This was achieved by the use of a swelling-agent, tri-methylbenzene (TMB). Characterization by transmission electron microscopy (TEM), X-ray diffraction pattern (XRD) and nitrogen sorption analysis showed a mesocellular foam like carbon structure composed of porous cells with internal hexagonally arranged channels. In addition to the 3 nm internal channels, there were larger mesopores connecting the cellular domains. These larger mesopores were formed in the interparticle voids created during carbonization. The dual porosity network structure had a high surface area (> 1000m²/Vg) and large pore volume (> 1.2 mL/g). When loaded with Pt-Ru nanoparticles, the PtRu/carbon became a good electrocatalyst and gave higher activity for methanol oxidation compared to a commercial catalyst.