Pt/Au composite monolayer films were fabricated by combining interfacial assembly and under-potential deposition (UPD) with redox replacement.Based on the Pt/Au composite monolayers,an organic linker-free method was proposed for the fabrication of sandwich-like Pt/Au composite multilayer films:(Pt/Au)n,Ptm/Au,and (Pt3/Au)k (n,m,or k represents the layer number).Electron microscopy was used to characterize the morphologies of the Au monolayer films and the Pt/Au composite multilayer films.For each type of composite multilayer films,a common characteristic was that the effective electroactive areas increased with an increase in the layer number.Additionally,the electrocatalytic activities of the composite multilayer films for methanol electrooxidation are systematically discussed by examining the catalytic current densities and its tolerance toward carbonaceous species.For the same series of composite multilayer films (Pt/Au)3,Pt3/Au,and (Pt3/Au)2 showed a higher catalytic current density than bulk Pt (Ptbutk).Among the three composite multilayer films,(Pt/Au)3 showed the best catalytic performance in terms of the current density and tolerance toward carbonaceous species.The tolerance of (Pt/Au)3 to carbonaceous species was found to be better than that of the commercial Pt/C catalyst.This better electrocatalytic activity may be attributed to the maximum synergistic effect between Au and Pt,which depends on the Pt:Au atomic ratio and also the arrangement of Pt and Au nanoparticles.%采用界面组装、欠电位沉积和氧化还原置换反应组合方法制备了单层Pt/Au复合薄膜,并且不需要任何有机偶联剂;组装单层Pt/Au复合薄膜为三类多层Pt/Au复合薄膜:(Pt/Au)n、Ptm/Au和(Pt3/Au)k(n、m和k分别为Pt/Au、Pt和Pt3/Au的层数).采用电子显微镜研究了Au纳米粒子单层膜和Pt/Au复合多层膜的形貌.对于所有的多层膜电极而言,其电化学活性面积随着层数的增加而增加.通过研究甲醇在每一类Pt/Au复合薄膜上的氧化电流密度,考察了其对甲醇的电催化和抗毒化性能.对于同一类复合薄膜而言,甲醇分别在(Pt/Au)3、Pt3/Au和(Pt3/Au)2电极上均具有最大的氧化电流密度,且优于本体Pt电极.在这三种电极中,(Pt/Au)3电极无论从电流密度上还是从抗毒化能力上讲,其性能是最好的,而且其抗毒化能力也优于商业Pt/C催化剂.这种良好的催化性能源于Au和Pt之间最大化的协同效应,这取决于Pt和Au原子比率以及Pt纳米层和Au纳米层之间的排布方式.
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