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Decarboxylation-Induced Defects in MOF-Derived Single Cobalt Atom@Carbon Electrocatalysts for Efficient Oxygen Reduction
Angewandte Chemie International Edition ( IF 16.1 ) Pub Date : 2021-07-31 , DOI: 10.1002/anie.202107053
Shuai Yuan 1 , Jinwei Zhang 1 , Linyu Hu 1 , Jiani Li 1 , Siwu Li 1 , Yanan Gao 2 , Qinghua Zhang 3 , Lin Gu 3 , Wenxiu Yang 1 , Xiao Feng 1 , Bo Wang 4
Affiliation  

Developing transition metal single-atom catalysts (SACs) for oxygen reduction reaction (ORR) is of great importance. Zeolitic imidazolate frameworks (ZIFs) as a subgroup of metal-organic frameworks (MOFs) are distinguished as SAC precursors, due to their large porosity and N content. However, the activity of the formed metal sites is limited. Herein, we report a decarboxylation-induced defects strategy to improve their intrinsic activity via increasing the defect density. Carboxylate/amide mixed-linker MOF (DMOF) was chosen to produce defective Co SACs (Co@DMOF) by gas-transport of Co species to DMOF upon heating. Comparing with ZIF-8 derived SAC (Co@ZIF-8-900), Co@DMOF-900 with more defects yet one fifth Co content and similar specific double-layer capacitance show better ORR activity and eight times higher turnover frequency (2.015 e s−1 site−1). Quantum calculation confirms the defects can weaken the adsorption free energy of OOH on Co sites and further boost the ORR process.

中文翻译:

MOF衍生的单钴原子@碳电催化剂中脱羧引起的缺陷,用于高效氧还原

开发用于氧还原反应 (ORR) 的过渡金属单原子催化剂 (SAC) 非常重要。沸石咪唑骨架 (ZIF) 作为金属有机骨架 (MOF) 的一个亚组,由于其大孔隙率和 N 含量而被区分为 SAC 前体。然而,形成的金属位点的活性是有限的。在此,我们报告了一种脱羧诱导的缺陷策略,通过增加缺陷密度来提高其内在活性。选择羧酸盐/酰胺混合接头 MOF(DMOF)通过加热时将 Co 物质气体传输到 DMOF 来生产有缺陷的 Co SAC(Co@DMOF)。与 ZIF-8 衍生的 SAC(Co@ZIF-8-900)相比,Co@DMOF-900 具有更多的缺陷,但具有五分之一的 Co 含量和相似的特定双层电容显示出更好的 ORR 活性和八倍的周转频率(2.015 e s-1 位点-1 )。量子计算证实,这些缺陷会削弱 OOH 在 Co 位点上的吸附自由能,并进一步促进 ORR 过程。
更新日期:2021-09-20
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