Room temperature and rapid synthesis of two-dimensional bimetallic NiCo-CAT MOFs by an electrochemical strategy for enhancing electrocatalytic oxygen evolution reaction

Abstract

Room temperature, rapid and large-scale preparation of 2D-metal organic frameworks (2D-MOFs) with high oxygen evolution reaction (OER) activity is still a challenge. Herein, a series of 2D NiCo-CAT MOFs were synthesized by a mild green electrochemical method with Ni and Co as metal sources and 2,3,6,7,10,11-hexahydroxytribenzene (HHTP) as the organic ligand. The synthesis conditions were fine-tuned by adjusting the solvent ratio, applied voltage, synthesis temperature, and reaction time. Electrochemical testing revealed that NiCo-CAT/CC exhibited a low overpotential of 307 mV at a current density of 10 mA cm⁻², accompanied by a small Tafel slope of 61.03 mV dec⁻¹ in a 1.0 M KOH solution (the dosage of Co²⁺ was 70 μmol). Further investigation shows that the rapid electron transfer, large electrochemical active area and exposure of more metal active sites in bimetallic NiCo-CAT enhanced the OER activity. This work has opened up a new pathway for the rapid preparation of OER catalysts using the electrochemical strategy, offering a green approach with short reaction times, low energy consumption, and high yields, making it ideal for future practical applications.