Redox-Active and Urea-Engineered-Entangled MOFs for High-Efficiency Water Oxidation and Elevated Temperature Advanced CO 2 Separation Cum Organic-Site-Driven Mild-Condition Cycloaddition.

Development of the multifaceted metal-organic framework (MOF) with in situ engineered task-specific sites can promise proficient oxygen evolution reaction (OER) and high-temperature adsorption cum mild-condition fixation of CO 2 . In fact, effective assimilation of these attributes onto a single material with advance performance characteristics is practically imperative in view of renewable energy application and carbon-footprint reduction. Herein, we developed a three-fold interpenetrated robust Co(II) framework that embraces both redox-active and hydrogen-bond donor moieties inside the microporous channel. The activated MOF demonstrates notable OER catalysis in alkaline medium via quasi-reversible Co 2+ /Co 3+ couple and unveils low overpotential with impressive 53.5 mV/dec Tafel slope that overpowers some benchmark, commercial, as well as contemporary materials. In particular, significantly increased turnover frequency (3.313 s -1 at 400 mV) and fairly low charge-transfer resistance (3.02 Ω) compared to Co 3 O 4 , NiO, and majority of redox-active MOFs together with 91% Faradaic efficiency and notable framework durability after multiple OER cycles endorse high-performance water oxidation. Pore-wall decked urea groups benefit appreciable CO 2 adsorption even at elevated temperatures with considerable MOF-CO 2 interactions and exhibit recurrent capture-release cycles at diverse temperatures. Interestingly, CO 2 selectivity displays radical upsurge with temperature rise, affording 40% improved CO 2 /N 2 value of 200 at 313 K, which outperforms many porous adsorbents and delineates real-time CO 2 scavenging potential. The guest-free MOF effectively catalyzes solvent-free CO 2 cycloaddition with broad substrate tolerance and satisfactory reusability under relatively mild condition. Opposed to the common Lewis acid-mediated reaction, two-point hydrogen-bonding activates the substrate, as supported from controlled experiments, juxtaposing the performance of an un-functionalized MOF and fluorescence modification-derived framework-epoxide interaction, providing valuable insights on unconventional cycloaddition route in the MOF.