No abstract

A robust and porous Ni-based metal–organic framework (MOF), NiL1, was assembled from Ni(II) ions and a dipyrazolate linker (L1 2–). A Ni(II)-anchored MOF catalyst Ni@NiL1-Sal has been successfully prepared by post-synthetic modification (PSM) condensation between NiL1 with salicylaldehyde, followed by chelation of Ni(II) ions by salicylaldimine as a secondary active site. Ni@NiL1-Sal with carbon black was found to exhibit enhanced electrocatalytic hydrogen evolution reaction (HER) performance (the smallest overpotential, 384 mV, and Tafel slope, 87 mV dec–1) when compared with primitive NiL1 and NiL1-Sal. Such improvement in HER highlights the creation of unambiguous secondary active sites as an avenue to the rational design of a functional MOF-based electrocatalyst.