Basal Plane‐Activated Boron‐Doped MoS2 Nanosheets for Efficient Electrochemical Ammonia Synthesis

Under the dual pressure of energy crisis and environmental pollution, ammonia (NH3 ) is an indispensable chemical product in the global economy. The electrocatalytic synthesis of NH3 directly from nitrogen and water using renewable electricity has become one of the most attractive and important topics. Basal plane-activated boron-doped MoS2 nanosheets (B-MoS2 ) as a non-noble metal catalyst with excellent performance for N2 electroreduction are synthesized by a facile one-step hydrothermal method. In 0.1 m Na2 SO4 solution, MoS2 nanosheets doped with 300 mg boric acid (B-MoS2 -300) give rise to a good ammonia yield rate of 75.77 μg h-1 mg-1cat. at -0.75 V vs. RHE, and an excellent Faradaic efficiency of 40.11 % at -0.60 V vs. RHE. In addition, the B-MoS2 -300 nanosheets show good selectivity and chemical stability, and no hydrazine (N2 H4 ) by-product is generated during the reaction. 15 N isotopic labeling confirms that nitrogen in produced ammonia originates from N2 in the electrolyte. On the one hand, the high conductivity of MoS2 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 MoS2 , 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-MoS2 , which makes the adsorption of N2 on the base plane easier and promotes the NRR.