Electrocatalytic nitrate reduction to ammonia coupled with organic oxidation

Electrocatalytic nitrate reduction using renewable energy is a potential approach to environmental remediation and ammonia production, yet it is hindered by sluggish kinetics and poor efficiency. Herein, a well-defined carbon nanosheet array-supported cobalt phosphide (CoP; CNs@CoP) electrocatalyst is synthesized, achieving remarkable performance for nitrate reduction to ammonia with a Faraday efficiency of 95.1% at −0.30 V vs. reversible hydrogen electrode (RHE) and a yield rate of 43.9 mg h−1 cm−2 at −1.0 V vs. RHE. Moreover, an electrocatalytic nitrate reduction coupled with glycerol oxidation system is constructed, which delivers dramatically enhanced ammonia production (15.2 mg h−1 cm−2) and gains high value-added formate (111.4 mg h−1 cm−2) at 1.8 V cell voltage. Preliminary technoeconomic analysis confirms the economic feasibility of the coupled system. We also design a new CO2 capture strategy by using as-prepared ammonia as absorbent, which is promising for sustainable ammonia synthesis and its application.