Selective nitrogen reduction to ammonia on iron porphyrin-based single-site metal–organic frameworks

Abstract

Constructing efficient catalysts for N₂ reduction into value added ammonia under ambient conditions is a considerable challenge. Herein, well-defined single-site metal–organic frameworks (MOFs, M–TCPP; M = Fe, Co, or Zn) were constructed and evaluated as electrocatalysts for N₂ reduction. The prepared Fe–TCPP exhibited prominent performance with a high NH₃ yield of 44.77 μg h⁻¹ mg_cat.⁻¹ and a faradaic efficiency of 16.23%, superior to that of all the reported molecular and MOF catalysts. The superior performance was ascribed to the highly effective N₂ activation at the Fe site, and benefited from the overall reaction thermodynamics advantage in the key reaction step of *NNH formation. This study gives an understanding of the intrinsic activity of well-defined catalysts in the electrocatalytic N₂ reduction, and provides atomic-level insights into the rational design and engineering of highly active catalysts for artificial N₂ fixation.