In Situ Synthesis of Cu x O/N Doped Graphdiyne with Pyridine N Configuration for Ammonia Production via Nitrate Reduction

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-08, Vol.20 (33), p.e2310467
• Main Authors: Li, Jian, Valenza, Roberto, Haussener, Sophia
• Format: Article
• Language: English
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202310467

Electroreduction of nitrate to ammonia provides an interesting pathway for wastewater treatment and valorization. Cu-based catalysts are active for the conversion of NO to NO but suffer from an inefficient hydrogenation process of NO . Herein, Cu O/N-doped graphdiyne (Cu O/N-GDY) with pyridine N configuration are in situ prepared in one pot. Benefiting from the synergistic effect of pyridinic N in GDY and Cu O, the prepared Cu O/N-GDY tested in a commercial H-cell achieved a faradaic efficiency of 85% toward NH at -0.5 V versus RHE with a production rate of 340 µmol h  mg in 0.1 M KNO . When integrating the Cu O/N-GDY in an anion exchange membrane flow electrolyzer, a maximum Faradaic efficiency of 89% is achieved at a voltage of 2.3 V and the production rate is 1680 µmol h  mg at 3.3 V in 0.1 M KNO at room temperature. Operation at 40 °C further promoted the overall reaction kinetics of NO to NH , but penalized its selectivity with respect to hydrogen evolution reaction. The high selectivity and production rate in this device configuration demonstrate its potential for industrial application.