(532ej) Design of a Novel Ru-Based Nrr Catalyst Using a Framework Integrating DFT and Kmc

Ammonia (NH₃) generation from nitrogen reduction is a very well-known, important chemical reaction. Until now, the industrial Haber-Bosch process enables mass production of ammonia, which is critical in enabling green energy and sustainable fertilizer. However, this process operates at high pressure and temperature because of the notoriously inert N₂ triple bond, causing severe environmental problems. To resolve this problem, an associative nitrogen reduction reaction (NRR) under ambient conditions has received tremendous attraction as an alternative approach, although there are a few remaining challenges that need to be addressed such as low ammonia production selectivity and rate. In this regard, Ruthenium (Ru) has been considered the most promising (and thus widely studied) catalyst, however, its low faradaic efficiency has restricted its widespread adoption in a variety of practical applications.

For the above-mentioned reason, we newly designed diverse Ru-based catalysts with greatly enhanced NRR catalytic activities, and suggested the best candidate that surpasses the conventional Ru. Furthermore, to get a theoretical insight into the NRR performance of the designed structures from thermodynamics and kinetics perspectives, we combined density functional theory (DFT) and kinetic Monte Carlo (kMC) simulations by considering realistic electrochemical reaction conditions such as the presence of explicit water solvent. By bridging the two methods, we analyzed N₂ selectivities for NRR initial reaction of designed structures and their overpotentials based on the thermodynamic Sabatier analysis. Additionally, based on the kinetic reaction rates available from the kMC simulations, we investigated adsorbent localization, surface coverage, reaction turnover frequency (TOF), and I-V curve as a function of time, temperature, and pressure. Here, our systematic investigations clearly reveal that the newly designed Ru-based candidate material has superior NRR catalytic activity to other conventional Ru-based catalysts by decreasing H poisoning, overpotential, and increasing TOF, current density.