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使用旋转电极技术考察了一系列碳载金纳米颗粒(颗粒平均尺寸处在3～14nm)在碱性电解质(0.5mol/LKOH)中对氧还原反应的催化行为.随着金纳米颗粒尺寸由14nm下降至3nm,其对氧还原反应的本征活性和质量比活性均呈现持续走高趋势;但金颗粒的纳米尺寸对氧还原反应的机理及分子氧还原过程中的电子转移数目并无显著影响.使用高分辨透射电镜技术表征了金纳米颗粒的形貌,通过对金颗粒表面不同位置原子的比例进行估算,发现金颗粒表面高能原子所占比例与金对氧还原反应的本征活性密切相关,表明高能表面原子决定着金催化剂对氧还原反应的本征活性.此外,还将金纳米颗粒对氧还原反应的本征催化活性与其表面电子结构进行了关联.
The catalytic behavior of a series of carbon-supported gold nanoparticles (average size of the particles ranging from 3 to 14 nm) on the oxygen reduction reaction in alkaline electrolyte (0.5 mol / L KOH) was investigated using a rotating electrode technique.As the size of the gold nanoparticles varied from 14 nm However, the nano-size of the gold particles had no significant effect on the mechanism of oxygen reduction reaction and the number of electron transfer in the molecular oxygen reduction process. The morphology of gold nanoparticles was characterized by high-resolution transmission electron microscopy. By estimating the atomic ratio at different positions on the surface of gold particles, it was found that the proportion of high-energy atoms on the surface of gold particles is closely related to the intrinsic activity of gold-oxygen reduction reaction. Indicating that the high-energy surface atoms determine the intrinsic activity of the gold catalyst for the oxygen reduction reaction.In addition, the intrinsic catalytic activity of the gold nanoparticles for the oxygen reduction reaction is also related to the surface electronic structure.