Sandwich-like WS₂@MoS₂ 2D/1D Core-Shell Heterostructures for Efficient Nitrogen Electroreduction to Ammonia

The electrocatalytic nitrogen reduction reaction (eNRR) into ammonia is considered a sustainable alternative to the traditional Haber-Bosch process. However, the problematic N₂ activation and the competing hydrogen evolution reaction (HER) significantly hinder achieving satisfactory performance in aqueous electrolytes. Herein, we synthesized an eNRR electrocatalyst featuring MoS₂ nanowire (NW) arrays that grow uniformly and vertically through intercalation between the interlayers of WS₂ nanosheets (NSs), forming sandwich-like WS₂@MoS₂ 2D/1D core-shell heterostructures. The thickness of WS₂ NSs is ∼100 nm, while MoS₂ NWs have a length of 71.49 ± 15.56 nm and a diameter of 8.56 ± 1.17 nm. This structure enhances the exposure of the basal planes and edges of MoS₂. Additionally, the MoS₂ NWs possess abundant lattice dislocations and vacancies in both Mo and S. The strong interfacial electron interactions between the WS₂ core and MoS₂ shell significantly enhance the catalytic activity for eNRR. As a result, the WS₂@MoS₂ heterostructures achieve a high NH₃ yield rate of 61.79 μg h^-1 cm^-2 and a Faradaic efficiency of 21.64% at -0.3 V vs RHE, surpassing that of both WS₂ and MoS₂ counterparts, as well as most other reported NRR electrocatalysts in aqueous electrolytes. This work offers valuable insights into the design of heterostructures to boost the activity and selectivity of eNRR to ammonia simultaneously.