Tuning electronic environment of B sites in boron carbonitride nanoribbon boosts catalytic activity of reducing N2 to NH3.

[Display omitted] • Homogeneous BCNs rich in B-C active sites and localized phase-separated BCNs rich in B-N active sites are designed. • Influence of the differed electronic environment on the NRR catalytic performances of BCN is theoretically studied by DFT. • The BCN nanoribbon is prepared by a self-assembly method, with the excellent NH 3 productivity and a high Faraday efficiency. The electrocatalytic nitrogen reduction reaction (NRR) to synthesize ammonia is an important and challenging task in chemistry, where low-cost, highly active non-metallic catalysts such as boron carbonitride (BCN) are still highly desired. Tuning the electronic environment of the active site B is an effective approach to improve the NRR performance of BCNs. However, the study on the mechanism of this effect has been seriously neglected. The diversity and controllability in atomic arrangements of BCN make it suitable for studying the relationship between the local chemical environment of boron and the catalytic properties. To this end, we design four kinds of BCN materials named as homogeneous BCN nanoribbon and BCN nanosheet enriched with B − C active sites and localized phase-separated BCN nanoribbon and BCN nanosheet rich in B − N active sites, and theoretically screen the homogeneous type BCN nanoribbons that have better NRR performances. Meanwhile, we experimentally demonstrate that the optimized charge redistribution of B atoms in BCN skeleton by tuning the electronic environment makes the B − C sites being the effective centers in NRR, and arising the excellent NH 3 productivity of 63.02 μg h−1 mg − 1 cat with a highest Faraday efficiency of 32.28 %. [ABSTRACT FROM AUTHOR]