Isostructural NiII Metal–Organic Frameworks (MOFs) for Efficient Electrocatalysis of Oxygen Evolution Reaction and for Gas Sorption Properties

Abstract

Design and synthesis of stable, active and cost-effective electrocatalyst for water splitting applications is an emerging area of research, given the depletion of fossil fuels. Herein, two isostructural NiII redox-active metal–organic frameworks (MOFs) containing flexible tripodal trispyridyl ligand (L) and linear dicarboxylates such as terephthalate (TA) and 2-aminoterphthalate (H2NTA) are studied for their 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 evolution reaction in alkaline conditions with an overpotential as low as 356 mV. Further, these 2D-MOFs exhibit excellent ability to adsorb water vapor (180–230 cc g−1 at 273 K) and CO2 (33 cc g−1 at 273 K). The presence of hydrophilic functionality in the frameworks was found to significantly enhance the electrocatalytic activity as well as H2O sorption.