Freestanding Cactus-Like Dual-Phase Bimetallic Metal–Organic Framework as a High-Efficiency Electrocatalyst for Water Oxidation

Realizing a high-efficiency electrochemical oxygen evolution reaction (OER) is a great challenge in water splitting and metal–air battery fields due to the slow reaction kinetics. Herein, a synchronous dual-phase synthetic strategy is developed to successfully construct a cactus-like dual-phase bimetallic metal–organic framework (MOF) on a nickel foam (NF) substrate (noted as NiFe-MOF@NF). It is constituted by Ni-main NiFe-MOF and Fe-main NiFe-MOF. When functioning as an anode, the freestanding cactus-like dual-phase NiFe-MOF@NF catalyst merely requires a lower overpotential of 277 mV to supply 100 mA cm–2 with robust stability (90% retainment of initial current density after 24 h chronoamperometry measurement). Density functional theory calculations on the NiFe-MOF@NF catalyst reveal that the combination of Ni and Fe has efficiently modulated the electron configuration of metal centers and optimized the absorption/desorption of OER oxygen-containing intermediates. Thus, we demonstrate a novel synchronous dual-phase synthetic strategy to engineer freestanding dual-phase electrocatalysts, which feature multiple synergetic effects considerably boosting OER performance for optimizing the energy conversion and storage system

Amorphous Metal–Organic Framework-Derived Electrocatalyst to Boost Water Oxidation

Amorphous metal–organic framework (MOF) materials have drawn extensive interest in the design of high-performance electrocatalysts for use in the electrochemical oxygen evolution reaction. However, there are limitations to the utilization of amorphous MOFs due to their low electrical conductivity and unsatisfactory stability. Herein, a novel amorphous–crystalline (AC) heterostructure is successfully constructed by synthesizing a crystalline metal sulfide (MS)-embedded amorphous Ni0.67Fe0.33-MOF, namely an MS/Ni0.67Fe0.33-MOF. It exhibits excellent catalytic performance (a low overpotential of 248 mV at 10 mA cm–2 with a small Tafel slope of 50 mV decade–1), durability, and stability (only 8% degradation of the current density at a constant voltage after 24 h). This work thus sheds light on the engineering of highly efficient catalysts with AC heterointerfaces for optimizing water-splitting systems