A new nitrogen fixation strategy: the direct formation of *N2- excited state on metal-free photocatalyst

N-2 fixation under mild conditions using renewable electricity or solar energy is a promising alternative to the century-old Haber-Bosch process; however, it is generally impeded by the initial hydrogenation and competitive hydrogen evolution reaction. Herein, a new N-2 fixation strategy is proposed via directly forming *N-2(-) excited state on metal-free boron-decorated diamond clusters (BDCs). Surface-doped B atoms facilitate the adsorption of N-2 and simultaneously suppress H+ due to the repulsion of Lewis acids. Excited state dynamics simulations demonstrate that valence electrons using the valence-band edge of BDCs as springboard are directly excited into the pi* orbitals of *N-2 under the illumination of similar to 4 eV light (far below similar to 11 eV for free N-2), which not only further improves the selectivity but also forms activated *N-2(-) excited states with sufficient lifetime (similar to 10 ns) for the initial hydrogenation. This work affords fresh insight to advance photocatalysis for sustainable NH3 production.

Automated summary

This study proposed a new strategy for N-2 fixation using metal-free boron-decorated diamond clusters, which creates excited states and improves selectivity under light illumination. This approach offers insights for advancing photocatalysis for sustainable NH3 production.