Ammonia is a mainstay chemical for critical industries, including global food production, pharmaceuticals, and textile manufacturing. 1 Annually, 175 million tons of ammonia are produced worldwide, with approximately 85% used to produce fertilizers essential for food security. 2 However, the current production relies on the Haber-Bosch process, an energy-intensive method that operates at high pressures (150–300 bar) and temperatures (400–500 °C). This process consumes 1–2% of the global energy supply and emits over 1% of total global CO₂ emissions annually. Moreover, centralized production facilities require extensive distribution networks, further increasing carbon emissions. 3,4 To meet the growing demand for ammonia, driven by population growth, increased food production needs, and emerging applications such as a hydrogen carrier, zero-carbon fuel, and power generation, finding sustainable production routes is crucial. For instance, the maritime sector alone is projected to consume 197 million metric tons of ammonia as fuel by 2050. 5 While the demand for ammonia is expected to rise significantly to an estimated 688 million tons annually by 2050, this growth presents an opportunity to transition to green ammonia production methods that eliminate CO₂ emissions. Developing sustainable, decentralized, and energy-efficient ammonia synthesis pathways is essential to support its expanding role in global energy systems while achieving climate targets, such as those outlined in the Paris Agreement. 6 An environmentally friendly alternative process is the electrochemical reduction of N₂ or nitrogen-containing compounds, such as nitrate, to produce ammonia using electricity generated from renewable energy sources. 7,8 In this work, we developed phthalocyanine-based and porphyrin based molecular catalysts using copper tetraphenyl porphyrin (CuTPP), copper phthalocyanine (CuPc), iron tetraphenyl porphyrin (FeTPP), Iron phthalocyanine (FePc) with and without substituents, and carbon nanotubes and evaluated their performance toward the electrochemical nitrate reduction to ammonia. We aimed to provide insight into the effects of iron and copper active sites, chemical composition, and substituents on the performance of molecular catalysts on electrochemical nitrate reduction reaction and decipher the role of the parameters mentioned above on the activity and selectivity of the catalysts. We used from advanced X-ray absorption spectroscopy and post-mortem transmission electron microscopy, X-ray diffraction, and density functional theory (DFT) to unravel catalysts evolution under reaction conditions and investigate the reaction mechanism. References: 1 Jung, W. & Hwang, Y. J. Material strategies in the electrochemical nitrate reduction reaction to ammonia production. Materials Chemistry Frontiers 5, 6803-6823 (2021). https://doi.org/10.1039/d1qm00456e 2 Wang, M. et al. Can sustainable ammonia synthesis pathways compete with fossil-fuel based Haber–Bosch processes? Energy & Environmental Science 14, 2535-2548 (2021). https://doi.org/10.1039/d0ee03808c 3 Wang, Y. et al. Enhanced Nitrate-to-Ammonia Activity on Copper–Nickel Alloys via Tuning of Intermediate Adsorption. Journal of the American Chemical Society 142, 5702-5708 (2020). https://doi.org/10.1021/jacs.9b13347 4 McEnaney, J. M. et al. Electrolyte Engineering for Efficient Electrochemical Nitrate Reduction to Ammonia on a Titanium Electrode. ACS Sustainable Chemistry & Engineering 8, 2672-2681 (2020). https://doi.org/10.1021/acssuschemeng.9b05983 5 Zhang, X. et al. Recent advances in non-noble metal electrocatalysts for nitrate reduction. Chemical Engineering Journal 403 (2021). https://doi.org/10.1016/j.cej.2020.126269 6 Lin, N., Wang, H., Moscardelli, L. & Shuster, M. The dual role of low-carbon ammonia in climate-smart farming and energy transition. Journal of Cleaner Production 469, 143188 (2024). https://doi.org/https://doi.org/10.1016/j.jclepro.2024.143188 7 Foster, S. L. et al. Catalysts for nitrogen reduction to ammonia. Nature Catalysis 1, 490-500 (2018). 8 Liang, X. et al. A two-dimensional MXene-supported metal–organic framework for highly selective ambient electrocatalytic nitrogen reduction. Nanoscale 13, 2843-2848 (2021). https://doi.org/10.1039/D0NR08744K