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

Constructing efficient catalysts for N-2 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 N-2 reduction. The prepared Fe-TCPP exhibited prominent performance with a high NH3 yield of 44.77 mu g 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 N-2 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 N-2 reduction, and provides atomic-level insights into the rational design and engineering of highly active catalysts for artificial N-2 fixation.