Viologen‐Cucurbit[7]uril Based Polyrotaxanated Covalent Organic Networks: A Metal Free Electrocatalyst for Oxygen Evolution Reaction

Abstract

AbstractViologen‐based covalent organic networks represent a burgeoning class of materials distinguished by their captivating properties. Here, supramolecular chemistry is harnessed to fabricate polyrotaxanated ionic covalent organic polymers (iCOP) through a Schiff‐base condensation reaction under solvothermal conditions. The reaction between 1,1′‐bis(4‐aminophenyl)‐[4,4′‐bipyridine]‐1,1′‐diium dichloride (DPV‐NH2) and 1,3,5‐triformylphloroglucinol (TPG) in various solvents yields an iCOP‐1 and iCOP‐2. Likewise, employing cucurbit[7]uril (CB[7]) in the reaction yielded polyrotaxanated iCOPs, denoted as iCOP‐CB[7]‐1 and iCOP‐CB[7]‐2. All four iCOPs exhibit exceptional stability under the acidic and basic conditions. iCOP‐CB[7]‐2 displays outstanding electrocatalytic Oxygen Evolution Reaction (OER) performance, demanding an overpotential of 296 and 332 mV at 10 and 20 mA cm−2, respectively. Moreover, the CB[7] integrated iCOP‐2 exhibits a long‐term stable nature for 30 h in 1 m KOH environment. Further, intrinsic activity studies like TOF show a 4.2‐fold increase in generation of oxygen (O2) molecules than the bare iCOP‐2. Also, it is found that iCOP‐CB[7]‐2 exhibits a high specific (19.48 mA cm−2) and mass activity (76.74 mA mg−1) at 1.59 V versus RHE. Operando‐EIS study evident that iCOP‐CB[7]‐2 commences OER at a relatively low applied potential of 1.5 V versus RHE. These findings pave the way for a novel approach to synthesizing various mechanically interlocked molecules through straightforward solvothermal conditions.