Bifunctional Electrocatalysts for Overall Water Splitting from an Iron/Nickel‐Based Bimetallic Metal–Organic Framework/Dicyandiamide Composite

Abstract

Pyrolysis of a bimetallic metal organic framework (MIL‐88‐Fe/Ni)‐dicyandiamide composite yield a Fe and Ni containing carbonaceous material, which is an efficient bifunctional electrocatalyst for overall water splitting. FeNi3 and NiFe2O4 are found as metallic and metal oxide compounds closely embedded in an N‐doped carbon ‐ carbon nanotube matrix. This hybrid catalyst (Fe‐Ni@NC‐CNTs) significantly promote the charge transfer efficiency and restrain the corrosion of the metallic catalysts, which is shown in a high OER and HER activity with an overpotential of 274 and 202 mV at 10 mA cm‐2 in alkaline solution, respectively. When this bifunctional catalyst was further used for H2 and O2 production in an electrochemical water‐splitting unit, it can operate in ambient air with a competitive gas production rate of 1.15 and 0.57 µl s‐1 for hydrogen and oxygen, respectively, showing its potential for practical applications.