The novel π-d conjugated TM2B3N3S6 (TM = Mo, Ti and W) monolayers as highly active single-atom catalysts for electrocatalytic synthesis of ammonia

Yongxiu Sun; Wenwu Shi; Yong-Qing Fu; Haijian Yu; Zhiguo Wang; Zhijie Li

doi:10.1016/j.jcis.2023.06.181

The novel π-d conjugated TM₂B₃N₃S₆ (TM = Mo, Ti and W) monolayers as highly active single-atom catalysts for electrocatalytic synthesis of ammonia

J Colloid Interface Sci. 2023 Nov 15;650(Pt A):1-12. doi: 10.1016/j.jcis.2023.06.181. Epub 2023 Jun 27.

Authors

Yongxiu Sun¹, Wenwu Shi¹, Yong-Qing Fu², Haijian Yu³, Zhiguo Wang⁴, Zhijie Li⁵

Affiliations

¹ University of Electronic Science and Technology of China, Chengdu 610054, PR China.
² Faculty of Engineering and Environment, Northumbria University, Newcastle Upon Tyne NE1 8ST, UK.
³ Department of Mechanical Engineer, Weihai Secondary Vocational School, Weihai 264213, PR China.
⁴ University of Electronic Science and Technology of China, Chengdu 610054, PR China. Electronic address: zgwang@uestc.edu.cn.
⁵ University of Electronic Science and Technology of China, Chengdu 610054, PR China. Electronic address: zhijieli@uestc.edu.cn.

PMID: 37392494
DOI: 10.1016/j.jcis.2023.06.181

Abstract

Recently, single-atom catalysts (SACs) are receiving significant attention in electrocatalysis fields due to their excellent specific activities and extremely high atomic utilization ratio. Effective loading of metal atoms and high stability of SACs increase the number of exposed active sites, thus significantly improving their catalytic efficiency. Herein, we proposed a series (29 in total) of two-dimensional (2D) conjugated structures of TM₂B₃N₃S₆ (TM means those 3d to 5d transition metals) and studied the performance as single-atom catalysts for nitrogen reduction reaction (NRR) using density functional theory (DFT). Results show that TM₂B₃N₃S₆ (TM = Mo, Ti and W) monolayers have superior performance for ammonia synthesis with low limiting potentials of -0.38, -0.53 and -0.68 V, respectively. Among them, the Mo₂B₃N₃S₆ monolayer shows the best catalytic performance of NRR. Meanwhile, the π conjugated B₃N₃S₆ rings undergo coordinated electron transfer with the d orbitals of TM to exhibit good chargeability, and these TM₂B₃N₃S₆ monolayers activate isolated N₂ according to the "acceptance-donation" mechanism. We have also verified the good stability (i.e., E_f < 0, and U_diss > 0) and high selectivity (U_d = -0.03, 0.01 and 0.10 V, respectively) of the above four types of monolayers for NRR over hydrogen evolution reaction (HER). The NRR activities have been clarified by multiple-level descriptors (ΔG_*N2H, ICOHP, and Ɛ_d) in the terms of basic characteristics, electronic property, and energy. Moreover, the aqueous solution can promote the NRR process, leading to the reduction of ΔG_PDS from 0.38 eV to 0.27 eV for the Mo₂B₃N₃S₆ monolayer. However, the TM₂B₃N₃S₆ (TM = Mo, Ti and W) also showed excellent stability in aqueous phase. This study proves that the π-d conjugated monolayers of TM₂B₃N₃S₆ (TM = Mo, Ti and W) as electrocatalysts show great potentials for the nitrogen reduction.

Keywords: 2D TM(2)B(3)N(3)S(6) monolayer; Density functional theory; Nitrogen reduction reaction; Single-atom catalyst.