N₂ electrochemical reduction on two dimensional transition metal monoborides: A density functional theory study

Abstract

Electrochemical reduction of N2 at ambient conditions is emerging as a promising route and can be powered by sustainable energies. Large overpotential and the competing hydrogen evolution reaction (HER) are the two major issues associated with the N2 reduction. Thus, the development of efficient electrocatalysts with low overpotential is of utmost significance for electrochemical nitrogen reduction reaction (NRR). In this theoretical study, we report a valuable insight toward a novel two dimensional (2D) transition metal monoboride (TMB) material possessing efficient electrocatalysts application for NRR, investigated by density functional theory method. Through systematically exploring the Gibbs free energy of N2 adsorption on the different TMB (TM = Cr, Mn, Fe, Co, Ni and Mo) nanosheets and analyzing adsorption energy of N2H and NH2 species on these catalysts, we found MoB nanosheets may be the optimum choice as an electrocatalyst for NRR. Moreover, our results also indicate that NRR on MoB nanosheets via the enzymatic pathway is the most favored pathway and *NH*NH → *NH*NH2 is potential‐limiting step with a very low applied overpotential of 0.14 V. In addition, the limiting potentials of NRR (−0.30 V) and HER (−0.48 V) on MoB nanosheet suggest that NRR is prefer to happen on the catalyst. Overall, this study demonstrates that MoB nanosheets as a novel 2D monolayer, which might be utilized as an efficient electrocatalyst for NRR at ambient conditions.

MBenes: progress, challenges and future

“…Therefore, MBenes are expected to be applied as electrode and electrocatalysis materials. The applications for energy storage and electrocatalysis have been widely investigated theoretically by rst principles methods, including anodes of Li, Na, Mg ion batteries and Li-S batteries, as well as electrocatalysis for the hydrogen evolution reaction (HER), 8,30,36,39,58,59 oxygen evolution reaction (OER), 59 oxygen reduction reaction (ORR), 59 nitrogen reduction reaction (NRR), [31][32][33]35,54,[60][61][62][63] carbon dioxide reduction reaction (CO 2 RR), 64,65 nitric oxide reduction reaction (NORR), 34,66 and urea production. 67…”

“…The NRR catalytic properties of MBenes have been studied by many researchers theoretically, which involves 20 M 2 B 2 (M ¼ Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y, Zr, Nb, Mo, Tc, Ru, Hf, Ta, W) and M 3 B 4 (M ¼ V, Nb, Ta) orth-MBenes as well as Mo 2 B 2 O 2 -based SACs. [31][32][33]35,54,[60][61][62][63] N 2 could be activated aer adsorbing on the bare transition metal surfaces of MBenes by the "donation & back-donation" mechanism, in which N 2 molecules donate electrons from the s* orbitals to the spare d orbitals in the transition metal atoms, while on the other hand, the occupied d orbitals of transition metal atoms backdonate electrons to the p* antibonding orbitals of N 2 , as illustrated in Fig. 9(d).…”

Transition‐Metal Borides (MBenes) as New High‐Efficiency Catalysts for Nitric Oxide Electroreduction to Ammonia by a High‐Throughput Approach

“…This work provides a new route to screening highefficiency catalysts for the development of NORR. A volcano plot provides an efficient approach to explore promising candidate catalysts and reaction mechanisms, [19,20] and volcano plots can be constructed by limiting the potential and determining the rate determining step (RDS). For example, the formation of different intermediates and establishment of the most preferable reaction path have been obtained from DFT studies.…”

Electrochemical catalysis of aluminum diboride thin film fabricated by radio-frequency magnetron sputtering

“…Inspired by the catalytic processes found in certain bacteria, where ammonia is synthesized through the reaction of protons and electrons, the electrochemical nitrogen reduction reaction (NRR, N 2 + 6H + + 6e − → 2NH 3 ) has emerged as a potential alternative pathway for ammonia synthesis. [23][24][25][26] Notably, bacterial NRR occurs at ambient temperature and pressure, making it amenable to renewable energy-driven processes. 27) To date, non-bacterial ammonia syntheses from N 2 , facilitated by both metallic and metal-free catalysts, cannot compete with NRR, because these processes are nitrogen-adsorption and decomposition-kinetic-limited reactions that are energy-intensive with relatively low yield.…”

“…[33][34][35] Moreover, 2D borides demonstrate excellent mechanical strength due to their covalent bonding, 36) while also displaying favorable nitrogen adsorption properties. 23) These exceptional characteristics advocate for the exploration of NRR catalysts, necessitating fundamental investigations into material synthesis, the role of crystallinity, and the electrical properties in NRR activity. However, the high temperatures and pressures in conventional hot press methods for fabricating 2D borides still prevent this type of studies.…”