Executive Summary : | Ammonia is an important chemical and can be accounted as an unconventional fuel for hydrogen storage. Mostly, NH3 is produced by the Haber–Bosch (HB) process at elevated temperature and pressure. The process required a huge amount of energy source and produces excessive amount of greenhouse gases which has a negative impact on the environment. There are several processes for NH3 synthesis and among those methods, renewable energy-driven, electrochemical nitrogen reduction (e-NRR) for NH3 production is an encouraging route in an environmental friendly conditions. Effective e-NRR has been demonstrated to be immensely challenging in practice because the competitive hydrogen evolution reaction (HER) which is always interfering the process due to its low redox potential in comparable with N2 reduction. (a) Catalyst design: We are proposing here, coinage metal-based cluster-assembled materials (CAMs) and atom-precise metal nanoclusters as active eNRR catalysts. In CAMs, the unique geometry of the cluster and appropriate choice of linker facilitates the charge-transfer pathway for effective electrocatalysis. Precise atomic control in structure is crucial for controlling the reactivity for desired reactions. It is advantageous to produce resilient mono-dispersed atom-precise clusters on a solid substrate for efficient catalytic activity. (b) Catalytic methodology: The products selectivity for NH3 synthesis is affected by the competitive HER. Among several strategies to inhibit HER, two important methods are as follows: (i) Catalyst engineering: The use of 2D CAMs or cluster @2D supports with well-defined structures may be more suitable for preferred eNRR because of their unique electronic structure and facile charge transfer pathway that may prefer bonding with N-adatoms rather than H-adatoms. (ii) Supporting cations: Proton migration through the double layer to the catalytic surface would be retarded if large amounts of hydrated cations (for example, K+) concentrated near surface of the diffusion layer. (c) Electrochemical cells and performance evolution: Based on the requirement for eNRR, the H-type cell will be adopted here as reactor. Stability and performance of the catalysts would be carried out by several matrices like, chronoamperometric experiments, Tafel slopes, turn-over frequency, etc. (d) NH3 detection: Precise detection of as-synthesized NH3 would be reported by using Nessler’s reagent method, indophenol blue method, and nuclear magnetic resonance spectroscopy methods. 1H-NMR equipped with 15N2 isotopic tracking will also identify the product. (e) Mechanistic study: To underscore the eNRR mechanism, computational (in collaboration) and in situ experimental studies will be carried out. During the NRR experiments (potential scan with specific rate), DRIFT IR spectra will be recorded with a specific spectral resolution for identifying the intermediates. |