Preparation of hard magnetic Co2C nanospheres as electrocatalysts for hydrogen evolution reaction

Cobalt carbide as a new type of transition metal carbides (TMACs) has received extensive attention in the field of magnetism and electrocatalysis. As one of the cobalt carbide materials, Co ₂C shows good hard magnetism. In this paper, we have designed a simple and efficient method to successfully prepare single-phase Co ₂C nanospheres. Co ₂C is synthesized by using Co ₃O ₄ as precursor and small molecule amino ethylenediamine as carbon source. The material exhibits excellent hard magnetic properties, with saturation magnetization up ( Ms) to 32.19 emu/g and coercivity up to 1111 Oe at room temperature. Co ₂C also demonstrats excellent hydrogen evolution reaction performance in 1 M KOH solution. Using nickel foam as the working electrode, the overpotential of only 92 mV can reach the current density of 10 mA cm ⁻², and the Tafel slope is 104 mV dec ⁻¹. This provides a new idea for the further development of synthetic cobalt carbide and its composite materials.