Wormholelike mesoporous carbon supported PtRu catalysts toward methanol electrooxidation

摘要

Wormholelike mesoporous carbons (WMCs) with three different pore diameters (Dp),namely WMC-F7 (Dp =8.5 nm),WMC-F30 (Dp=4.4nm),and WMC-F0 (Dp=3.1 nm) are prepared via a modified sol-gel process.Then PtRu nanoparticles with the panicle size (dpt) of ～3.2 nm supported on WMCs are synthesized with a modified pulse microwave-assisted polyol method.It is found that the pore diameter of WMCs plays an important role in the electrochemical activity of PtRu toward alcohol electrooxidation reaction.PtRu/WMC-F7 with Dp ＞ 2dpt exhibits the largest electrochemical surface area (ESA) and the highest activity toward methanol electrooxidation.With the decrease in Dp,PtRu/WMC-F30 and PtRu/WMC-F0 have much lower ESA and electrochemical activity,especially for the isopropanol electrooxidation with a larger molecular size.When Dp is more than twice dpt,the mass transfer of reactants and electrolyte are easier,and thus more PtRu nanoparticles can be utilized and the catalysts activity can be enhanced.