铂/聚邻甲基苯胺/碳材料掺杂碳糊电极对甲醇的催化氧化

Methanol Electrocatalytic Oxidation on Pt/Poly(o-toluidine) Film/Activated Carbon Doped Graphite Carbon Paste Electrode

以石墨和液体石蜡油为主要原料,分别制备了掺杂不同量多壁碳纳米管(MWCNT)、石墨烯(GRA)、电容活性炭(YEC)和电池活性炭(YBC)的多种碳糊底电极Y-CPE(Y代表各种掺杂碳材料,CPE代表纯碳糊电极).采用恒电位法在-0.10 V(vs.Ag/Ag Cl)电位下将铂电沉积到这些电极上.结果表明,当电池碳的含量为14%时,Pt/YBC-CPE(14%)复合电极对甲醇具有最好的电催化氧化活性.采用恒电位方法在0.85 V(vs.Ag/Ag Cl)电位下将聚邻甲基苯胺(POT)电聚合沉积到纯碳糊电极CPE和含有电池碳的YBC-CPE(14%)电极上,得到复合电极POT/CPE和POT/YBC-CPE(14%),再通过恒电位方法将铂电沉积到这2个复合电极上.扫描电镜(SEM)观察结果表明,在Pt/CPE,Pt/YBC-CPE(14%),Pt/POT(6.5 mC)/CPE和Pt/POT(6.5 mC)/YBC-CPE(14%)4个复合电极中,在Pt/POT/YBC-CPE(14%)复合电极上的铂粒子的尺寸最小,并且Pt/POT(6.5 mC)/YBC-CPE(14%)复合电极电催化氧化甲醇活性最高.在POT(6.5 mC)/CPE和POT(6.5 mC)/YBC-CPE(14%)上Pt纳米颗粒的电沉积过程是一个近似的3D成核过程.研究还发现,复合电极Pt/POT/CPE和Pt/POT/YBC-CPE电催化氧化甲醇的活性随POT膜厚度的增加先增大后减少,存在一个最佳的膜厚度.

Various liquid oil-bound carbon paste electrodes were prepared from the mixtures of graphite powders and paraffin（CPE）,multi-walled carbon nanotubes and graphite powders and paraffin（MWCNTCPE）,graphene and graphite powders and paraffin（GRA-CPE）,activated capacitors carbon and graphite powders and paraffin（YEC-CPE）,activated batteries carbon and graphite powders and paraffin（YBC-CPE）,respectively.Poly（o-toluidine）（POT） film was prepared by constant potential deposition at 0.85 V（vs.Ag ｜AgCl） in monomer solution at the surface of CPE and YBC-CPE（14%）（14% refers to the mass fraction of YBC in the carbon mixture materials） with various film growth charges.Platinum nanoparticles were successfully electrodeposited on Y-CPE（Y refers to the various carbon materials mentioned above except graphite powders）,POT/CPE,POT/YBC-CPE（14%） at a fixed potential of -0.10 V（vs.Ag ｜ AgCl） in 0.5 mol/L H_2SO_4 solution containing 3.0 mmol/L H_2PtCl_6.In order to learn about the instantaneous or progressive nucleation process of platinum on composite electrodes,non-dimensional plots of（I/I_m）~2 vs.t/t_m of the experimental were compared with theory through the expressions.The morphologies of platinum nanoparticles were characterized by scanning electron microscopy（SEM）.The SEM images reveal that the presence of YBC and POT influences the size of platinum nanoparticle.The electrocatalytic activities of as-formed Pt/CPE,Pt/POT/CPE,Pt/YBC-CPE and Pt/POT/YBC-CPE（14%） towards the electrooxidation of methanol were evaluated by cyclic voltammetry（CV）.The experimental results indicate that compared with other POT/Y-CPE,Pt/POT/YBC-CPE（14%） has the best electrocatalytic activity towards methanol oxidation in an acidic medium.