LAUSR

Electrocatalytic nitrite (NO2−) reduction (NO2RR) to ammonia (NH3) is a promising green technology for producing NH3 with high efficiency. Cobalt macrocyclic complexes have attracted great interest because of their ability to selectively convert NO2− to NH3, but suffer from low NH3 yields. Herein, cobalt porphyrin conjugated polymer on carbon nanotubes (CoPCOP@CNT) is reported to display exceptional NO2RR performance with a large NH3 yield of 133.39 mg h−1 mgCoP−1 at −1.0 V and high Faradaic efficiency (FE) of 98.0% at −0.8 V. Utilizing CoPCOP@CNT as the catalyst cathode, the Zn‐NO2− battery exhibits remarkable power density (5.34 mW cm−2), open‐circuit voltage (≈1.45 V), FE (94.6%), and NH3 yield (29.15 mg h−1 mgCoP−1). The active intermediates and reaction pathways of CoPCOP in NO2RR process are revealed by differential electrochemical mass spectroscopy and theory calculations. This work highlights the potential of electrocatalysts based on metal porphyrins for the conversion of nitrogenous pollutant into NH3.