Pal Hiranmoy, Karmakar Arun, Sadhukhan Arnab, Sharma Rahul Kumar, Paul Srayasee, Addicoat Matthew A, Nishiyama Yusuke, Pathak Biswarup, Kundu Subrata, Banerjee Rahul
Department of Chemical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India.
Centre for Advanced Functional Materials, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, India.
J Am Chem Soc. 2025 Jun 18;147(24):20406-20416. doi: 10.1021/jacs.5c02083. Epub 2025 Jun 6.
Covalent organic framework (COF)-based electrocatalysts for water oxidation are usually designed by inducing polarization into an organic framework. The most common methodology "heteroatom insertion" suffers from lower catalytic activity than metalated systems. Herein, we introduce a strategy of polarity induction into organic frameworks by complexing electrolyte's alkali metal using crown ether. We have synthesized a series of porous crystalline COFs with different sizes of crown ether units, having different alkali metal binding abilities. COF-catalysts having crown ethers in their backbone show oxygen and hydrogen evolution (OER and HER) performance in alkaline electrolytes. Electrocatalytic performances of various COF-catalysts have also been studied while changing the alkali metal of the electrolyte solution. The most efficient catalyst B18C achieved a current density of 20 and 100 mA cm at an overpotential (η and η) of 287 ± 1 and 362 ± 8 mV (for the OER) in 1 M KOH (pH = 13.6), with good electrocatalytic stability (16 h chronopotentiometry study showed a 2 mV potential change at 25 mA cm current density). Notably, B18C COF also exhibited good OER performance in 1 M KSO (pH = 6.3) with an overpotential (η) of 471 mV. Additionally, a promising alkaline HER activity of B18C (η = 310 ± 5 mV) leads to an overall water-splitting performance in 1 M KOH ( = 1.784 V @ 20 mA cm).
用于水氧化的共价有机框架（COF）基电催化剂通常通过在有机框架中引入极化来设计。最常见的方法“杂原子插入”的催化活性低于金属化体系。在此，我们介绍一种通过冠醚络合电解质的碱金属将极性引入有机框架的策略。我们合成了一系列具有不同尺寸冠醚单元、具有不同碱金属结合能力的多孔晶体COF。在其主链中含有冠醚的COF催化剂在碱性电解质中表现出析氧和析氢（OER和HER）性能。在改变电解质溶液的碱金属时，还研究了各种COF催化剂的电催化性能。最有效的催化剂B18C在1 M KOH（pH = 13.6）中，在过电位（η和η）为287 ± 1和362 ± 8 mV（对于OER）时实现了20和100 mA cm的电流密度，具有良好的电催化稳定性（16小时计时电位法研究表明在25 mA cm电流密度下电位变化2 mV）。值得注意的是，B18C COF在1 M KSO（pH = 6.3）中也表现出良好的OER性能，过电位（η）为471 mV。此外，B18C具有有前景的碱性HER活性（η = 310 ± 5 mV），导致在1 M KOH中实现整体水分解性能（在20 mA cm时 = 1.784 V）。
