Herein, a series of Cu–N–C-type catalysts was prepared and characterized by high-temperature annealing of Cu^IItetrephenylporphyrin (Cu^IITPP)-coated reduced graphene oxide (rGO). These catalysts were used for the selective removal of simulated nitrate, nitrogen selectivity, and energy utilization efficiency, which were achieved at 73.9%, 93.9%, and 25.4%, respectively. Dual-metal Cu_xM_1−x–N–C catalysts were also prepared and characterized. The nitrate removal (74.9%), nitrogen selectivity (95.0%), and energy utilization efficiency (35.5%) were higher for the Cu_0.8Ni_0.2–N–C dual-metal catalyst.