Here we report the electrochemical determination of the surface-area-to-volume ratio (SA/V) of Au nanospheres (NSs) attached to electrode surfaces for size analysis. The SA is determined by electrochemically measuring the number of coulombs of charge passed during the reduction of surface Au₂O₃ following Au NS oxidation in HClO₄, whereas V is determined by electrochemically measuring the coulombs of charge passed during the complete oxidative dissolution of all of the Au in the Au NSs in the presence of Br^– to form aqueous soluble AuBr₄^–. Assuming a spherical geometry and taking into account the total number of Au NSs on the electrode surface, the SA/V is theoretically equal to 3/radius. A plot of the electrochemically measured SA/V versus 1/radius for five different-sized Au NSs is linear with a slope of 1.8 instead of the expected value of 3. Following attachment of the Au NSs to the electrode and ozone treatment, the plot of SA/V versus 1/radius is linear with a slope of 3.5, and the size based on electrochemistry matches very closely with those measured by scanning electron microscopy. We believe the ozone cleans the Au NS surface, allowing a more accurate measurement of the SA.

中文翻译：

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基于电化学测量的表面积与体积比的金属纳米颗粒尺寸确定

在这里，我们报告了电化学测定附着在电极表面的金纳米球（NSs）的表面积与体积之比（SA / V），以进行尺寸分析。SA是通过电化学测量在HClO _4中Au Au氧化后表面Au ₂ O ₃还原后表面Au ₂ O ₃还原过程中通过的电荷库仑数而确定的，而V是通过电化学测量所有氧化完全溶解后通过的电荷库仑数来确定的。金在金中的NS溴的存在^-以形成水溶性AuBr ₄ ^-。假设球形几何形状并考虑到电极表面上Au Au的总数，则SA / V理论上等于3 /半径。五个不同尺寸的Au NSs的电化学测量的SA / V相对于半径的图是线性的，斜率是1.8，而不是预期值3。在Au NSs附着到电极和臭氧处理之后，该图SA / V相对于1 /半径的线性关系具有3.5的斜率，并且基于电化学的尺寸与通过扫描电子显微镜测得的尺寸非常接近。我们相信臭氧可以清洁Au NS表面，从而可以更准确地测量SA。