利用单晶旋转圆盘电极技术（Hanging Meniscus Rotating Disk Electrode, HMRD）在硫酸和高氯酸溶液中分别研究了甘氨酸修饰的Pt(111)电极表面氧分子的电催化还原反应. 实验发现：在硫酸溶液中，经甘氨酸修饰的Pt(111)电极表面的氧还原活性明显提高，其中氧还原的半波电位与Pt(111)电极的相比正移约0.1 V，而在高氯酸溶液中，甘氨酸修饰的Pt(111)电极的活性几乎没有发生变化. 该实验结果表明：甘氨酸修饰的Pt(111)电极一方面抑制了SO42-在电极表面的吸附，另一方面又能在电极表面提供相邻的空位供氧分子吸附. 通过与文献中报道的CN-修饰的Pt(111)电极上的氧还原结果的对比，可以推测甘氨酸修饰的Pt(111)电极表面氧还原活性提高是由于甘氨酸在Pt(111)表面可能先被氧化成CN-后吸附在电极表面，进而促进了氧分子的电催化还原反应.
Oxygen reduction reaction (ORR) on glycin (NH2CH2COOH) modified Pt(111) electrode has been investigated using hanging meniscus rotating disk electrode system (HMRD) in 0.05 mol•L-1 H2SO4 and 0.1 mol•L-1 HClO4 solutions, respectively. Cyclic voltammograms of the glycin modified Pt (111) electrode measured in 0.05 mol•L-1 H2SO4 solution similar to that of CN- modified Pt(111) electrodes, demonstrating that sulfate adsorption is strongly inhibited at the glycin modified Pt(111). From the polarization curve of ORR recorded in 0.05 mol•L-1 H2SO4 solution, it is found that the ORR activity at the glycin modified Pt (111) is greatly enhanced with the half wave potential (E1/2) of ORR being shifted ca. 0.1 V positively, which is close to the activity of ORR at the unmodified Pt(111) in 0.1 mol•L-1 HClO4 solution. The improved ORR activity is explained by geometric effect due to the formation of well organized CN- adlayer at Pt(111) from the oxidative decomposition of glycin, which effectively inhibits the adsorption of sulfate anions.
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