Atom-by-atom electrodeposition of single isolated cobalt oxide molecules and clusters for studying the oxygen evolution reaction
Atom-by-atom electrodeposition of single isolated cobalt oxide molecules and clusters for studying the oxygen evolution reaction
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DOI：
10.1073/pnas.2002168117
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发表时间：
2020-06-09
影响因子：
11.1
通讯作者：
Bard, Allen J.
中科院分区：
文献类型：
--
作者：
Jin, Zhaoyu;Bard, Allen J.
我们报告了一个电沉积协议制备孤立的钴氧化物单分子（Co 1 Ox）和簇（ConOy）的碳纤维纳米电极。制备的沉积物能够在碱性介质中产生明确的析氧反应（OER）稳态伏安图，其中等效半径（r（d））根据电催化放大模型通过氢氧化物氧化的极限电流来估计。通过原子-原子（atom-by-atom）技术从飞摩尔的Co ~（2+）溶液中获得的孤立团簇的尺寸可以达到0.21 nm（r（d）），这大约是钴氧化物中Co-O键的长度。因此，该存款接近于仅具有一个钴离子的Co 1 Ox单分子的存款，钴离子是钴基析氧催化剂的最小单元。此外，在给定的电流密度下，OER对ConOy沉积物的尺寸依赖性催化在较小的簇上显示出更快的相对速率，这意味着单分子催化剂显示出上级OER活性。
We report an electrodeposition protocol for preparing isolated cobalt oxide single molecules (Co1Ox) and clusters (ConOy) 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 Co2+ 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 Co1Ox 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 ConOy 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.