Green synthesis of urea under ambient conditions by electrochemical co‐reduction of N2 and CO2 gases using effective electrocatalyst essentially pushes the conventional two steps (N2 + H2 = NH3 and NH3 + CO2 = CO(NH2)2) industrial process at high temperature and high pressure, to the brink. The single step electrochemical green urea synthesis process has hit a roadblock due to the lack of efficient and economically viable electrocatalyst with multiple active sites for dual reduction of N2 and CO2 gas molecules to urea. Herein, copper phthalocyanine nanotubes (CuPc NTs) having multiple active sites (such as metal center, Pyrrolic‐N3, Pyrrolic‐N2, and Pyridinic‐N1) as an efficient electrocatalyst which exhibits urea yield of 143.47 µg h–1 mg–1cat and faradaic efficiency of 12.99% at –0.6 V versus reversible hydrogen electrode by co‐reduction of N2 and CO2 are reported. Theoretical calculation suggests that Pyridinic‐N1 and Cu centers are responsible to form CN bonds for urea by co‐reduction of N2 to NN* and CO2 to *CO, respectively. This study provides the new mechanistic insight about the successful electro‐reduction of dual gases (N2 and CO2) in a single molecule as well as rational design of efficient noble metal‐free electrocatalyst for the synthesis of green urea.

Electrocatalytic ammonia (NH3) synthesis through the nitrogen reduction reaction (NRR) under ambient conditions presents a promising alternative to the famous century-old Haber–Bosch process. Designing and developing a high-performance electrocatalyst is a compelling necessity for electrochemical NRR. Specific transition metal based nanostructured catalysts are potential candidates for this purpose owing to their attributes such as higher actives sites, specificity as well as selectivity and electron transfer, etc. However, due to the lack of a well-organized morphology, lower activity, selectivity, and stability of the electrocatalysts make them ineffective at producing a high NH3 yield rate and Faradaic efficiency (FE) for further development. In this work, stable β-cobalt phthalocyanine (CoPc) nanotubes (NTs) have been synthesized by a scalable solvothermal method for electrochemical NRR. The chemically synthesized CoPc NTs show excellent electrochemical NRR due to high specific area, greater number of exposed active sites, and specific selectivity of the catalyst. As a result, CoPc NTs produced a higher NH3 yield of 107.9 μg h–1 mg–1 cat and FE of 27.7% in 0.1 M HCl at −0.3 V vs RHE. The density functional theory calculations confirm that the Co center in CoPc is the main active site responsible for electrochemical NRR. This work demonstrates the development of hollow nanostructured electrocatalysts in large scale for N2 fixation to NH3.

Ammonia forms the fundamental agricultural constituent and vital energy provenance of a clean hydrogen mediator. Ammonia production leads to immense energy utilization and drastic environmental repercussion. It is a daunting task to design and synthesize competent catalysts for reduction of nitrogenous species (nitrogen or nitrates, by the nitrogen reduction reaction (NRR) or nitrate reduction reaction (NO 3 RR) process, respectively) into ammonia. Cobalt(II) phthalocyanine (CoPc) nanotubes were effectively wrapped by 2D graphene sheets to produce a (1D−2D) heterostructure catalyst, which plays the role of a competent electrocatalyst for the NRR as well as NO 3 RR. The electrocatalyst showed an ammonia yield rate and a Faradaic efficiency of 58.82 μg h −1 mg −1 cat and 95.12%, respectively, for the NO 3 RR and for NRR 143.38 μg h −1 mg −1 cat and 43.69%, respectively. Bader charge investigation revealed the transport of charge to Co−N 4 active sites from reduced graphene oxide (RGO), which aids during the production of intermediates NNH* for nitrogen reduction and *NOH for nitrate reduction along with suppression of the parasitic HER, thereby demonstrating good selectivity and Faradaic efficiency. This work showcases new mechanistic discernment about the role of work function, interfacial charge transport, and electrocatalytic overpotential for the nitrogen/nitrate reduction reaction.

The industrial production of urea involves two step process, reaction of nitrogen and hydrogen to form ammonia followed by the reaction of the ammonia with carbon dioxide, so the process...

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