炭载体孔径对Pt_2Sn_1/蠕虫孔炭催化剂乙醇电氧化活性的影响

Dependences of Activities of Pt_2Sn_1/Wormhole-like Mesoporous Carbon Catalysts for Ethanol Electrooxidation Reaction on Pore Diameters of Carbon Supporters

分别以孔径为8.5nm、4.4nm和3.1nm的3种蠕虫孔炭WMC-F7、WMC-F30和WMC-F0为载体,合成了纳米Pt2Sn1/WMC催化剂。XRD与透射电镜结果表明3种载体上的催化剂平均粒径均为3.0nm,其电化学性能却相差很大。研究发现蠕虫孔炭载体的孔径显著影响Pt2Sn1催化剂的电化学性能:当载体孔径(Dp)大于2倍催化剂平均粒径(dPt)时,催化剂(即Pt2Sn1/WMC-F7)的电化学活性面积(ESA)和乙醇电氧化(EOR)活性均为最高;当以另外两种孔径的蠕虫孔炭作载体时,Pt2Sn1催化剂活性很差。这主要归因于WMC-F7的大孔径有利于传质,提高了催化剂的利用率及乙醇电氧化活性。

Wormhole-like mesoporous carbons（WMC）with pore diameters of 8.5nm,4.4nm and 3.1nm,namely WMC-F7,WMC-F30,and WMC-F0 respectively,were used as catalyst supporters to load Pt2Sn1 nanoparticles to synthesize nano-Pt2Sn1/WMC catalysts.XRD and TEM analyses indicated that the diameters of Pt2Sn1nanoparticles（dPt）on the three supporters were similar to each other（about 3.0nm）,but further experiments revealed that pore diameter of the WMC supporter（Dp）had obvious impact on the catalytic activity of Pt2Sn1 towards ethanol electrooxidation reaction.The Pt2Sn1/WMC-F7 catalyst whose pore diameter was 2times larger than dPtexhibited the biggest electrochemical surface area（ESA）and highest electrocatalytic activity for ethanol oxidation reaction（EOR）.However,in the cases of WMC-F30（dPtDp2dPt）and WMC-F0（Dp=dPt）,the catalysts obtained much lower ESA and EOR activity with respect to WMC-F7（Dp2dPt）.This can be attributed to the improved mass transfer in the case of WMC-F7.