酞菁钴及其衍生物修饰电极对分子氧的电催化还原

在玻碳电极上采用吸附法制备了四溴代酞菁钴(CoPcBr₄)、酞菁钴(CoPc)和四-α-(2,2,4-三甲基-3-戊氧基)酞菁钴(CoPc(OC₈H₁₇)₄)修饰电极。利用循环伏安法和线性扫描伏安法研究了修饰电极在酸性介质中对分子氧的电催化还原，比较了不同取代基的酞菁钴对电催化性质的影响。结果表明，它们对分子氧还原均具有良好的电催化活性，其中酞菁钴和四-α-(2,2,4-三甲基-3-戊氧基)酞菁钴对O₂的催化是2电子还原生成H₂O₂，与裸电极相比，O₂的还原峰电位分别向正方向移动了0.33和0.48 V。而四溴代酞菁钴修饰电极在-0.1和-0.7 V附近产生的2个还原峰，说明它催化O₂到H₂O₂的还原以后还可以促进H₂O₂继续还原到H₂O，最终实现O₂的4电子还原。

Electrocatalytical of Reduction of Oxygen at Cobalt Phthalocyanine and Its Derivative Modified Electrodes

Tetrabromophthalocyanine cobalt (CoPcBr₄), phthalocyanine cobalt (CoPc) and tetra-α-(2,2,4-trimethyl-3-pentyloxy)phthalocyanine cobalt (CoPc(OC₈H₁₇)₄) modified electrodes were prepared on glass carbon (GC) electrodes by the adsorption method. Electrocatalytic reduction of molecular oxygen by the modified electrodes was studied in acidic media by means of cyclic voltammetry and linear sweep voltammetry. The effects of phthalocyanine cobalt with different substituted groups on electrocatalytic property were compared. The results indicate that they have good electrocatalytic activity for molecular oxygen reduction. CoPc and CoPc(OC₈H₁₇)₄ could catalyze O₂ to give H₂O₂ via two-electron transfer and the reduction peak potentials of O₂ positively shifted 0.33 V and 0.48 V respectively compared with the bare GC electrode. There are two reduction peaks at about -0.1 V and -0.7 V in the voltammogram obtained at CoPcBr₄ modified electrode, indicating that it catalyzed the reduction of O₂ to H₂O₂ and then sequentially reduced H₂O₂ to H₂O. Finally, it completed the four-electron reduction of O₂.