Evaluating the efficiency of single-double atom catalysts in electrochemical NH3 production from NO based on CN monolayers

Abstract

The electrochemical NO reduction reaction (NORR) for the synthesis of NH₃ from nitric oxide (NO) presents a promising alternative to the conventional Haber process for ammonia production. However, exploring suitable catalysts for the NO-to-NH₃ conversion remains a significant challenge due to the absence of effective screening methods. In this study, we implemented a strategic approach known as the SAAS (stability, adsorption, activity, and selectivity) strategy, which employs four pivotal descriptors to comprehensively screen for efficient catalysts. This approach was applied to 27 transition metals to evaluate their potential as either single-atom (SA) or homonuclear double-atom (DA) catalysts for the conversion of NO to NH₃. Consequently, Hf₂–CN emerged as a stable catalyst for the NORR, exhibiting high selectivity for NH₃ production. Notably, DA catalysts demonstrated a distinct reaction mechanism compared to their SA counterparts, attributed to the synergistic effects of the diatomic configuration. This study provides a theoretical foundation for developing SA and DA catalysts for the conversion of NO to NH₃ and offers valuable insights for future experimental investigations in enhancing NORR efficiency.