Synergistic Promotion of the Electrochemical Reduction of Nitrogen to Ammonia by Phosphorus and Potassium

In the process of electrochemical ammonia synthesis using an aqueous solution as the electrolyte, most protons will preferentially compete for electrons for hydrogen generation. Herein, the carbon cloth loaded with Nano-Fe was used as the cathode, and a K3PO4 solution was used as the electrolyte. The electrochemical reduction of N-2 to NH3 was investigated. It was found that the K3PO4 electrolyte had an obvious promotion effect on the ammonia synthesis efficiency compared with other electrolytes. It was confirmed that phosphorus and potassium had a synergistic effect on the ammonia synthesis efficiency. K+ can effectively prevent H+ from adsorbing to the active site of a catalyst surface, thus inhibiting the formation of hydrogen. The solubility of the phosphate solution for N-2 is better than that of other aqueous electrolyte solutions, thus effectively improving the ammonia production efficiency. The highest ammonia yield was 79.0 +/- 5x10(-11) mol . s(-1) . cm(-2), and the faraday efficiency reached 16.68 %. These results provide an effective way to improve the conversion yield of electrochemical ammonia synthesis in water systems.