Wormholelike mesoporous carbons as the support for Pt_2Sn_1 towards ethanol electrooxidation: Effect of pore diameter

摘要

Pt_2Sn_1 nanoparticles supported on wormholelike mesoporous carbons (WMCs) with three different pore diameters, namely WMC-F7, WMC-F30, and WMC-F0 have been synthesized by adopting a modified pulse microwave-assisted polyol method. The pore diameters (D_p) of WMC-F7, WMC-F30, and WMC-F0 are 8.5 nm, 4.4 nm, and 3.1 nm respectively, while the particle size of Pt_2Sn_1 (D_(pt)) on each support is identical (~ 3 nm). Based on the experimental results, it has been found that the pore diameter plays an important role in the electrochemical activity of Pt_2Sn_1 catalysts towards ethanol electrooxidation reaction (EOR). Pt_2Sn_1/ WMC-F7 catalyst exhibits the highest electrochemical surface area (ESA) and activity towards EOR. Moreover, Pt_2Sn_1/WMC-F7 gives the comparable activity to the Pt_2Sn_1 supported on the commercial XC-72 carbon. However, in the cases of WMC-F30 (D_pt < Dp < 2 D_(pt)) and WMC-F0 (Dp = D_(pt)) as the supports, the corresponding catalysts obtain much lower ESA and EOR activity with respect to WMC-F7 (Dp > 2 D_(pt)). This could be attributed to the easy accessibility of Pt_2Sn_1 nanoparticles in the case of WMC-F7 with Dp > 2 D_(pt) for the easy fuel transportation, and consequently the EOR activity has been greatly improved.