期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2020
卷号：117
期号：23
页码：12651-12656
DOI：10.1073/pnas.2002168117
出版社：The National Academy of Sciences of the United States of America
摘要：We report an electrodeposition protocol for preparing isolated cobalt oxide single molecules (Co 1 O x ) and clusters (Co n O y ) on a carbon fiber nanoelectrode. The as-prepared deposits are able to produce well-defined steady-state voltammograms for the oxygen evolution reaction (OER) in alkaline media, where the equivalent radius ( r d ) is estimated by the limiting current of hydroxide oxidation in accordance with the electrocatalytic amplification model. The size of isolated clusters obtained from the femtomolar Co 2 solution through an atom-by-atom technique can reach as small as 0.21 nm ( r d ) which is approximately the length of Co–O bond in cobalt oxide. Therefore, the deposit was close to that of a Co 1 O x single molecule with only one cobalt ion, the minimum unit of the cobalt-based oxygen-evolving catalyst. Additionally, the size-dependent catalysis of the OER on Co n O y deposits shows a faster relative rate on the smaller cluster in terms of the potential at a given current density, implying the single molecular catalyst shows a superior OER activity.
