Dual-site N-oxidation engineering enables modulated polarization in covalent organic frameworks for efficient photocatalytic N2 reduction

Abstract

N-oxidation of imine linkages and pyridine moieties in pyridine-based covalent organic frameworks induces dual-site polarization. Due to the optimized polarization density and plentiful N+-O- polar units, TFPyB-O-COF exhibits an exceptional NH3 production rate of 519.8 µmol g-1 h-1 for photocatalytic N2 reduction, which is proposed to proceed via an alternating association mechanism.