Soft magnetic Fe5C2–Fe3C@C as an electrocatalyst for the hydrogen evolution reaction

Abstract

Herein, cubic iron carbides encapsulated in an N-doped carbon shell (ICs@NC) were prepared by a simple two-step method. The two-step method included the preparation of iron oxalate dihydrate and the process of calcination with ethylenediamine. By changing the calcination temperature, we could control the type of iron carbide formed. Moreover, the prepared iron carbide@N-doped carbon core–shell particles exhibited regular cubic shapes and soft magnetic properties with high saturation magnetization. More importantly, we investigated the electrocatalytic activity of the iron carbide@N-doped carbon catalysts for the hydrogen evolution reaction (HER). The results show that the Fe₅C₂–Fe₃C@NC catalyst has efficient HER catalytic activity with an overpotential of 209 mV@10 mA cm⁻².