The electrocatalytic reduction of nitrate is an efficient and green method for NH₃ production. In this study, a Co-containing MOF with a stable three-dimensional carbon framework that offers abundant metal active sites is prepared as a precursor to a Co-N-C electrocatalyst. Facile pyrolysis of the three-dimensional MOF affords the desired Co-N-C electrocatalyst, which exhibits excellent stability, an NH₃ yield of 1.12 mmol h⁻¹ mg⁻¹, and faradaic efficiency of 86.7% at −0.23 V in a 0.1 M KOH/0.1 M KNO₃. The excellent activity and durability are ascribed to the highly exposed active centres, large surface area, and high porosity structure. N doping allows the electronic properties to be modulated and provides outstanding stability owing to the strong interaction between the nitrogen-doped carbon support and Co nanoparticles. This study presents a simple and efficient synthesis strategy for the production of non-noble-metal electrocatalysts with abundant active sites for the nitrate reduction reaction.