The synergistic effect of hard magnetic Co2C and soft magnetic CoFe improves electrocatalytic overall water splitting performance

In order to solve the problem of environmental pollution caused by fossil fuel emissions, electrocatalytic overall water splitting is a very promising energy conversion device. In the field of large-scale overall water splitting, it is particularly important to develop new non-precious metal electrocatalysts. In this paper, we successfully prepared CoFe@Co₂C@Co/NF by hydrothermal synthesis of CoFe-LDH as the precursor and small molecule amine ethylenediamine as the C source. CoFe@Co₂C@ Co/NF shows excellent electrocatalytic performance in alkaline environment. CoFe@ Co₂C@Co-0.2/NF can provide low overpotential of 53 mV and 246 mV to reach 10 mA cm^-2 current density in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. In addition, CoFe@Co₂C@Co-0.2/NF was used as the anode and cathode of the electrolytic cell system for overall water splitting, and the current density of 10 mA cm^-2 can be reached with a voltage of only 1.57 V, which is superior to the commercial electrolytic cell system composed of Pt/C and RuO₂. The material exhibits a good coupling effect of soft and hard magnetic exchange. This provides new insights into the development of transition metal carbides as high-performance electrocatalysts.