Selective electrochemical nitrogen fixation to ammonia catalyzed by a novel microporous vanadium phosphonate via the distal pathway.

Herein, a microporous organic-inorganic hybrid, vanadium phosphonate (VPn) material has been developed. With the combined advantages of the periodic organic-inorganic skeleton, a regular microporous channel with a crystalline pore wall, and good surface area, VPn displays electrocatalytic NRR activity with a selective NH3 yield (11.84 µg h-1 mgcat-1), faradaic efficiency of 26.29% at -0.6 V and high stability up to 15 h. The isotopic labeling experiment also verifies the electrosynthesis of NH3 both qualitatively and quantitatively. The theoretical simulation reveals that the associative distal route serves as the most favourable pathway during the NRR, with the first protonation step of *N2 leading to *NNH as the potential determining step.