Design ands ynthesis of stable, active and cost-effective electrocatalystf or water splitting applicationsi sa n emerging area of research, given thed epletion of fossil fuels. Herein, two isostructuralN i II redox-activem etal-organic frameworks (MOFs) containing flexible tripodal trispyridyl ligand (L)a nd linear dicarboxylates such as terephthalate (TA) and 2-aminoterphthalate (H 2 NTA) are studied fort heir catalytic activity in oxygen evaluation reaction( OER). The 2D-layered MOFs form 3D hydrogen bonded frameworks containing one-dimensional hydrophilic channels that are filled with water molecules. The electrochemical studies reveal that MOFs display an efficient catalytic activity towards oxygen evolutionr eactioni na lkaline conditions with an overpotential as low as 356 mV.F urther,t hese 2D-MOFs exhibit excellenta bility to adsorb water vapor (180-230 cc g À1 at 273 K) and CO 2 (33 cc g À1 at 273 K). The presence of hydrophilic functionality in the frameworks was found to significantly enhancet he electrocatalytic activity as well as H 2 Os orption.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.

Table of Contents S1. 1 HNMR of ligand. S2-S7. Comparison of simulated and experimental PXRD pattern for complexes (1-7). S8-S14. FT-IR spectra for complexes (1-6).S15. TGA for complexes (2, 3 and 5). S17-S22. Comparison of PXRD pattern for complexes (1-6) after dye absorption.S23-S28. Comparison of PXRD pattern before and after adsorption-desorption isotherm for complexes 1-6. S29. Crystal violet dye absorption by complex 3 in aqueous solution. S30. UV graphs for MO absorption of complexes.

Design of adsorbents with high stability and efficiency to achieve rapid uptake and high capacity for dye pollutants is a key challenge in environmental remedies. Herein, we have design and synthesized three triazene-based imine and azine functionalized covalent organic frameworks (COFs 1–3) via the formation of imine bonds by the condensation of a flexible tripodal tri aldehyde (TFPT) with linear diamines. The COFs are characterized by elemental analysis, FTIR, solid-state NMR, TGA, FESEM, TEM, and DRS. They exhibit permanent porosity with high surface areas and N2 uptake capacities of 540, 1600, and 2235 cc/g by COFs 1–3, respectively. They are found to be chemically and thermally stable and exhibit moderate hydrogen storage capacities. Photophysical studies reveal that COFs 1–3 exhibited low band gap values of 3.0, 2.5, and 2.25 eV, respectively, indicating their semiconducting nature. All three materials are highly luminescent, and their emission maxima are found to depend on the nature of the diamine linker. Further, COFs 1–3 are highly stable in water and function as robust adsorbents, as evidenced by their high rapid uptake capacity (>96%) toward anionic (MO, CR) and cationic (MB, CV) organic dye pollutants from their respective aqueous solutions (2.5 × 10–5 M).

Four new MOFs were shown to have appreciable proton conductivities, selective adsorption of water vapor over nitrogen and a tendency to selectively adsorb cationic dyes such as methylene blue and crystal violet.