The electrochemical nitrate reduction reaction (NO3-RR) is a novel green method for ammonia synthesis. However, the lack of sufficient catalysts has hindered the development of the NO3-RR. This research develops a transformation of porous CoP@N-C/CC into porous phosphorus-rich CoP4@N-C/CC through high-temperature calcination. Due to its unique phosphating-rich structure, CoP4@N-C/CC exhibits an excellent Faraday efficiency (FE: 92.3%) and NH3 yield (610.2 μmol h-1 cm-2). Such a catalyst with more P-P bonds can provide more active sites, effectively enhancing the adsorption and reaction processes of reactant molecules. In addition, the catalyst has good durability and catalytic stability, which provides a possibility for the future application of electrocatalytic ammonia production.