Diamondoid Ni(II) Coordination Polymer as an Electrocatalyst for Hydrogen and Oxygen Evolution Reactions and Overall Water Splitting.

We have successfully synthesized a new Ni(II)‐based coordination polymer (CP) [Ni2(cis‐1,4‐chdc)2(4,4′‐bpy)3(H2O)2] (1); (cis‐1,4‐ H2chdc=cis‐1,4‐cyclohexanedicarboxylic acid and 4,4′‐bpy=4,4′‐bipyridine) employing slow diffusion method in a single pot technique. The connectivity of Ni(II) ions and bridging cis‐1,4‐chdc ligand gives rise to a three‐dimensional (3D) framework with 2‐fold interpenetrated diamondoid topology. Interestingly, the synthesized CP acts as efficient catalyst for electrocatalytic water splitting. The water oxidation activity of compound 1 exhibits Tafel slope equivalent to 361.48 mV.dec−1 for hydrogen evolution reaction (HER) and 353.53 mV.dec−1 for oxygen evolution reaction (OER) in an alkaline medium while almost similar values of Tafel slope for HER and OER equivalent to 287.33 mV.dec−1 and 289.93 mV.dec−1 respectively in acidic medium. Thus, the compound 1 has excellent efficacy in catalyzing HER and OER in acidic as well as alkaline medium, which is ascribed to its distinctive 3D architecture. [ABSTRACT FROM AUTHOR]