Heptanuclear brucite disk with cyanide bridges in a cocrystal and tracking its pyrolysis to an efficient oxygen evolution electrode

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2019,（22）
• 页码范围: 1667-1674
• 页数: 8页
• 语种: 英文

摘要

The development of efficient oxygen evolution reaction (OER) catalysts is still lacking in exploration of the mechanism of controlled pyrolysis of precursors among new material platforms.Here,a novel Co-based coordination molecular cluster has been first introduced as precursor to obtain metallic cobalt core shelled by N-doped carbon (Co@NC) structure which operates as an oxygen evolution electrode.Specifically,a new cocrystal compound,[Co117(μ3-CN)6(mmimp)6] [Co11Cl3N(CN)2]·3CH3OH (Co7+1,mmimp =2-methoxy-6-((methylimino)-methyl)phenol),was isolated consisting of Brucite disks of cobalt where the usual bridging μ3-OH is replaced by μ3-CN produced by the in-situ decomposition of dicyanamide (N≡C-N-C≡N-).The cobalt atoms are bonded through the nitrogen atom of the cyanide.Remarkably,time dependent thermogravimetric-mass spectrometry (TG-MS) analysis was utilized to track its pyrolysis pro cess.It allowed us to propose a possible formation process of the Co@NC structure from Co7+1.Interestingly,an extremely superior OER electrode is optimized for Co@NC-600 having the lowest overpotential of 257 mV at 10 mA/cm2 in 1 mol/L KOH solution.The present study pins down the importance of clusters of transition metals on realizing distinct nanostructures operating as highly efficient OER electrocatalyst.