Fe/Ni bimetallic organic framework with varying anions as robust electrocatalyst for oxygen evolution reaction

Abstract

The performance of the metal−organic frameworks (MOFs) will be affected when the anions added were different. Herein, bimetallic FeNi-MOF was synthesized by hydrothermal method with nickel foam as substrate, the effects of four anions (Cl − , NO 3 − , CH 3 COO − , SO 4 2− ) on the materials performance of MOF were investigated. The MOF prepared when added chloride ion with the overpotential at 100 mA•cm −2 as 247 mV. Meanwhile, the stability test at 100 mA cm −2 for 12 h had no obvious change which exhibited high electrochemical stability. The analysis demonstrated that the superior performance of the MOF prepared when added chloride ion was attributed to the low charge transfer resistance, increased active area, exposure more active sites. This work would shed some lights for facile synthesis of ultrahigh performance OER catalyst by adjusting the anion of the precursor. • The addition of chloride ions is conducive to the coordination between ligands and metal ions. • The multilayer nanosheet structure exposes more active sites and improves the oxygen evolution performance. • Improve sample conductivity, reduce charge transfer resistance and energy loss.