Transition-metal-free boron doped SbN monolayer for N2 adsorption and reduction to NH3: A first-principles study

Electrochemical nitrogen reduction reaction (NRR) in ambient condition is an efficient and sustainable method to synthesize NH3. In this work, first-principles study was used to discuss the NRR process on B atom doped SbN monolayer. The adsorption of N-2 on B-Sb17N18 and B-S18N17 was calculated including the adsorption energy, adsorption distance, and the charge density difference (CDD). Five different reaction pathways of NRR were taken into consideration and the stability of B-SbN was investigated. The results show that, because the energy of unoccupied orbital in sp(3) hybridization of B atom is much lower than that in 2pz orbitals, the adsorption of N-2 on B-Sb18N17 shows much larger adsorption energy (-1.01 eV with end-on pattern) compared to that of the adsorption on B-Sb17N18. For five different pathways, the 1, 2, and 4 pathways have a smaller limiting potential of about 0.52 V and the limiting step is: *N-2 + H+ + e(-) -> *NNH. The 3 and 5 pathways have a larger limiting potential of 0.57 V with hydrogenation step: *NHNH2 + H+ + e(-) -> *NH2NH2. The B-Sb18N17 is structurally and thermally stable even at 500 K. Our theoretical prediction indicates that B atom substitutionally doped SbN monolayer can be a kind of high-performance metal-free NRR catalyst for NH3 synthetization, and the work provides attempts for designing and exploring 2D metal-free NRR catalysts. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

The study explored the electrochemical nitrogen reduction reaction (NRR) on B atom doped SbN monolayer using first-principles approach, revealing the adsorption behavior of N-2 and different reaction pathways. Results showed that B-Sb18N17 is a promising high-performance catalyst for NH3 synthesis and remains structurally stable at elevated temperatures.