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.

DFT is applied to identify the active sites of NiPc for NRR and its catalytic origination. Accordingly, NiPc nanorods, synthesized by solvothermal method, exhibit NH3 yield rate of 85 μg h−1 mgcat−1 and FE of 25% at −0.3 V vs. RHE.

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The growing demands for ammonia in agriculture and transportation fuel stimulate researchers to develop sustainable electrochemical methods to synthesize ammonia ambiently, to get past the energy-intensive Haber-Bosch process. However, the conventionally used aqueous electrolytes limit N 2 solubility, leading to insufficient reactant molecules in the vicinity of the catalyst during electrochemical nitrogen reduction reaction (NRR). This hampers the yield and production rate of ammonia, irrespective of how efficient the catalyst is. Herein, we introduce an aqueous electrolyte (NaBF 4 ), which not only acts as an N 2 -carrier in the medium but also works as a full-fledged “co-catalyst” along with our active material MnN 4 to deliver a high yield of NH 3 (328.59 μg h −1 mg cat −1 ) at 0.0 V versus reversible hydrogen electrode. BF 3 -induced charge polarization shifts the metal d-band center of the MnN 4 unit close to the Fermi level, inviting N 2 adsorption facilely. The Lewis acidity of the free BF 3 molecules further propagates their importance in polarizing the N≡N bond of the adsorbed N 2 and its first protonation. This push-pull kind of electronic interaction has been confirmed from the change in d-band center values of the MnN 4 site as well as charge density distribution over our active model units, which turned out to be effective enough to lower the energy barrier of the potential determining steps of NRR. Consequently, a high production rate of NH 3 (2.45 × 10 −9 mol s −1 cm −2 ) was achieved, approaching the industrial scale where the source of NH 3 was thoroughly studied and confirmed to be chiefly from the electrochemical reduction of the purged N 2 gas.

Nanostructured transition metal dichalcogenides are demonstrated to be potential catalysts to produce molecular hydrogen through electroreduction of water. Finding an efficient and cost-effective catalyst as a substitute for a platinum-based catalyst for sustainable hydrogen production is still a major issue, more so for large-scale production. Herein, we have designed dendritic ferroselite (FeSe 2 ) hybrid nanocomposites with 2D g-C 3 N 4 and reduced graphene oxide (rGO) nanosheets, that is, FeSe 2 /g-C 3 N 4 and FeSe 2 / rGO as electrocatalysts for hydrogen evolution reaction (HER). Interestingly, FeSe 2 /rGO exhibited higher performance compared to FeSe 2 /g-C 3 N 4 . The highly conductive 2D FeSe 2 /rGO hybrid with an aligned curvy rippling surface and dendritic morphology demonstrates an onset potential of 218 mV at a current density of 10 mV/ cm 2 versus reversible hydrogen electrode in comparison to that of FeSe 2 /g-C 3 N 4 showing an onset potential of 437 mV. The detailed density functional theory (DFT) calculations were performed to investigate the intrinsic catalytic sites and Gibbs free energy (ΔG H* ) of hydrogen adsorption for the HER process. The DFT calculations displayed 0.33 V less overpotential for carbon atoms of g-C 3 N 4 (0.97 V) compared to rGO (1.3 V). In contrast, hybrids of FeSe 2 /rGO (0.86 V) display lower overpotential when compared to FeSe 2 /g-C 3 N 4 (1.63 V), which is in agreement with experimental results. Electrochemical impedance spectroscopy reveals lower charge transfer resistance (R ct ) for FeSe 2 /rGO. The high hydrogen evolution activity of FeSe 2 /rGO is due to the electrocatalytic synergistic effect of iron diselenide and rGO, contributing to the optimum free energy for HER and improved electron mobility.

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