Basal Plane-Activated Boron-Doped MoS 2 Nanosheets for Efficient Electrochemical Ammonia Synthesis.

Under the dual pressure of energy crisis and environmental pollution, ammonia (NH 3 ) is an indispensable chemical product in the global economy. The electrocatalytic synthesis of NH 3 directly from nitrogen and water using renewable electricity has become one of the most attractive and important topics. Basal plane-activated boron-doped MoS 2 nanosheets (B-MoS 2 ) as a non-noble metal catalyst with excellent performance for N 2 electroreduction are synthesized by a facile one-step hydrothermal method. In 0.1 m Na 2 SO 4 solution, MoS 2 nanosheets doped with 300 mg boric acid (B-MoS 2 -300) give rise to a good ammonia yield rate of 75.77 μg h -1  mg -1 cat. at -0.75 V vs. RHE, and an excellent Faradaic efficiency of 40.11 % at -0.60 V vs. RHE. In addition, the B-MoS 2 -300 nanosheets show good selectivity and chemical stability, and no hydrazine (N 2 H 4 ) by-product is generated during the reaction. 15 N isotopic labeling confirms that nitrogen in produced ammonia originates from N 2 in the electrolyte. On the one hand, the high conductivity of MoS 2 guarantees guarantees a high electron transfer rate from nitrogen to ammonia; on the other hand, the successful incorporation of heteroatom B enlarges the interlayer spacing of MoS 2 , and the B atom can act as an active site for basal plane activation, providing more active sites for the nitrogen reduction reaction (NRR). Density functional theory calculations show that the doping of B activates the base plane of 1T-MoS 2 , which makes the adsorption of N 2 on the base plane easier and promotes the NRR.