Unveiling Chemically Robust Bimetallic Squarate-Based Metal–Organic Frameworks for Electrocatalytic Oxygen Evolution Reaction

摘要

Here, this work reports an innovative strategy for the synthesis of chemicallyrobust metal–organic frameworks (MOFs), and applies them as catalysts forthe electrocatalytic oxygen evolution reaction (OER). A bimetallic squaratebasedMOF (Sq-MOF) with a zbr topology serves as an excellent platform forelectrocatalytic OER owing to its open porous structure, high affinity towardwater, and presence of catalytically active 1D metal hydroxide strips. Byregulating the Ni~(2+) content in a bimetallic squarate MOF system, the electrochemicalstructural stability toward OER can be improved. The screeningof various metal ratios demonstrates that Ni_3Fe_1 and Ni_2Fe_1 Sq-zbr-MOFsshow the best performance for electrocatalytic OER in terms of catalyticactivity and structural stability. Ni_2Fe_1 Sq-zbr-MOF shows a low overpotentialof 230 mV (at 10 mA cm~(?2)) and a small Tafel slope of 37.7 mV dec~(?1), with anexcellent long-term electrochemical stability for the OER. Remarkably, theseoverpotential values of Ni_2Fe_1 Sq-zbr-MOF are comparable with those of thebest-performing layered double hydroxide (LDH) systems and outperformsthe commercially available noble-metal-based RuO_2 catalyst for OER underidentical operational conditions.