Screening of borophene-supported highly active and selective single-atom catalysts for electrocatalytic nitrogen reduction reactions

Abstract

Ammonia (NH3) is an ideal zero-carbon clean energy source because of its substantial hydrogen capacity, high-energy density and facile transportability. Compared to disadvantages of Haber–Bosch processes, such as demanding reaction conditions, high energy consumption and inefficiency, the electrocatalysis nitrogen reduction reaction (NRR) can achieve green synthesis of NH3 due to mild reactive conditions. Utilizing density functional theory (DFT), explored the potential of borophene-supported transition metals as single atom catalysts (SACs) for NRR. The NRR pathways and Gibbs free-energy (ΔG) of the selected V@Bβ12, Cr@Bβ12, Zr@Bβ12 and Mo@Bβ12 were studied in detail after rigorous screening processes. The limiting potentials of NRR in optimal path are -0.10, -0.27, -0.18 and -0.07 V, respectively, which are excellent catalysts for NRR. Under operating voltage conditions, TM@Bβ12 has excellent ability to resist surface oxidation and inhibit hydrogen evolution reaction (HER). In addition, V@Bβ12, Cr@Bβ12, Zr@Bβ12 and Mo@Bβ12 have good selectivity for NRR. Cr@Bβ12 and Mo@Bβ12 are also potential catalysts for HER. The source of TM@Bβ12 catalytic activity in NRR fully confirms the good conductive properties, and the transmission of the charge contribute to improve catalytical activity of NRR. This paper provides theoretical guidance on the synthesis of a new type of NRR catalyst.