Cooperative active sites in ferrocene-nickel metal-organic framework catalysts for efficient and stable ammonia electrosynthesis

Abstract

Electrochemical nitrate reduction reaction (NO3RR) to ammonia offers a sustainable and environmentally friendly pathway for future ammonia production with reduced carbon emissions. Developing electrocatalysts exhibiting high activity and stability at low applied potentials while featuring well-defined catalytic active sites remains a critical challenge in NO3RR research. Herein, we present ferrocene-nickel based metal-organic framework (FcNi-MOF) as a highly efficient and stable NO3RR electrocatalyst, achieving a near-100 % Faradaic efficiency for ammonia at -0.2 VRHE, also maintaining its performance for a long time under the same potential. This performance surpasses the current NO3RR catalysts based on first-row transition metals or MOFbased materials. The cooperative reaction between catalytic active sites of ferrocene and nickel significantly enhances the activity of ammonia production. Moreover, we discovered that nitrate can inhibit the phase transition of MOF-based catalyst, resulting in remarkable enhancement of the catalytic stability. This work highlights the synergistic catalytic functionality and robust stability of multicomponent MOFs, presenting a promising pathway not only for future NO3RR research but also for broader electrochemical applications.