Koushik Mitra

This review provides a “puzzle-cube” framework for magnetoelectrocatalysis by connecting advanced materials, mechanisms, and electrochemical applications towards sustainable chemical transformations.

Electrochemical techniques for nitrogen and carbon transformations have recently experienced a spike in attention, coinciding with the growing demand for environmentally friendly and efficient processes. This review investigates the electrochemical conversion of nitrogenous molecules to value‐added products using a metal (M) phthalocyanine (Pc)‐based electrocatalyst. The review is mostly focused on nitrogen reduction to ammonia, nitrate/nitrite reduction to ammonia, nitrogen oxidation to nitric acid, urea formation from dinitrogen (N ₂ )/nitrogenous oxide (NO _x ), and carbon dioxide (CO ₂ ) reduction at the same time, and other similar reactions. This review aims for alternatives to traditional methods that consume significant amounts of energy and emit a lot of greenhouse gases by using cutting‐edge electrocatalyst engineering and a thorough understanding of how they work. A lot of various types of phthalocyanine systems have shown promise as catalysts for electrochemical applications. A better understanding of reaction mechanism and catalyst stability has been achieved through computational modeling and electrochemical characterization (including in situ study). Another focus is to highlight recent advancements, problems, and potential future directions in developing environmentally friendly, scalable, and efficient electrocatalytic systems for the transformation of nitrogen and carbon‐based reactants to generate value‐added products.

Nitrite (NO ₂ ⁻ ) is a dangerous pollutant that is often found in groundwater sources and endangers human health. In addition to nitrite removal requirements, electrocatalytic nitrite reduction reaction (eNO ₂ RR) holds promise for value‐added ammonia (NH ₃ ) production at room temperature. In this study, a solvothermal technique for the preparation of nickel phthalocyanine (NiPc) is used as a highly active electrocatalyst for the conversion of NO ₂ ⁻ to NH ₃ under ambient conditions. The NiPc catalyst shows a remarkable Faradaic efficiency (FE) of 90.1% at −0.9 V versus RHE with maximum ammonia yield rate of 14667 µg h ⁻¹ mg _cat. ⁻¹ at −1.0 V versus RHE in 0.1 M Na ₂ SO ₄ containing 0.1 M NaNO ₂ solution. Furthermore, the catalyst exhibits exceptional long‐term stability during chronoamperometry tests. These findings boost the future ammonia production from nitrite reduction for sustainable development.

Electrochemical urea synthesis under ambient conditions offers a promising alternative to traditional methods, yet suffers from inefficient production due to poor binding of reactants to the catalyst surface, leading to competitive pathways. In this study, we report an electrochemical route for urea synthesis by dual reduction of CO₂ and N₂ gases using iron phthalocyanine (FePc) catalyst. The FePc electrocatalyst showed a urea yield rate of 357 µmol h⁻¹ g_cat⁻¹ with a Faradaic efficiency (FE) of 14.36% at −0.4 V versus RHE. This work offers an awareness into the development of an electrochemical route for the efficient electrosynthesis of urea via C─N coupling.

Using low and optimized magnetic field along with electric field is a novel strategy to facilitate electrochemical nitrite reduction. Here, we report for the first time on the synthesis of ammonia via magneto-electrocatalytic methods that use spin-thrusted β-MnPc in a magnetic field of 95 mT. The calculated rate of ammonia generation was 16603.4 µg h-1 mgcat-1, which is almost twice that of the non-polarized MnPc catalyst. Additionally, the faradaic efficiency at –0.9V vs. RHE was found to be 92.9%, significantly higher compared to the non-polarized MnPc catalyst. In presence of external magnetic field, MnPc catalysts provide a better electron transfer channel which results in a lower charge transfer resistance and hence better electrochemical performances. DFT result further verifies that magnetic field induced β-MnPc has a lower potential barrier (0.51 eV) for the protonation of NO* (PDS) than non-polarized β-MnPc (1.08 eV), which confirms the enhanced electrochemical nitrite reduction to ammonia aided by external magnetic field.