Theoretical Exploration on the Role of Magnetic States to the N2 Fixation behaviors of 2D Transition Metal Tri-borides (TMB3 s).

Abstract

Fixing nitrogen (N2 ) by electrosynthesis method has become a promising way to ammonia (NH3 ) production, nevertheless, developing electrocatalysts combining long-term stable and low-cost feathers are still a great challenge to date. Using comprehensive first-principles calculations, we herein investigate the potential of a new class of two-dimensional (2D) transition metal tri-borides (TMB3 s) as nitrogen reduction reaction (NRR) electrocatalysts, and explore the effect of magnetic orders on the NRR. Our results show that the TMB3 s can sufficiently activate N2 and convert it to NH3 . Particularly, TiB3 is identified as a high-efficiency catalyst for NRR because of its low limiting potential (-0.24 V) and good suppression of the competitive hydrogen evolution reaction (HER). For the first time, we present that these TMB3 s with various magnetic states exhibit different performances in the adsorption of N2 and NRR intermediates, and minor effect on activation of N2 . Besides, VB3 , CrB3 , MnB3 , and FeB3 monolayers possess the superior capacity to suppress surface oxidation via the self-activating process, which reduces * O/* OH into * H2 O under NRR electrochemical conditions, thus favoring the N2 electroreduction. This work paves the way for finding high-performance NRR catalysts for transition metal borides and pioneering the research of magnetic states effects in NRR.