Sandwich-like WS@MoS 2/1D 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 N activation and the competing hydrogen evolution reaction (HER) significantly hinder achieving satisfactory performance in aqueous electrolytes. Herein, we synthesized an eNRR electrocatalyst featuring MoS nanowire (NW) arrays that grow uniformly and vertically through intercalation between the interlayers of WS nanosheets (NSs), forming sandwich-like WS@MoS 2/1D core-shell heterostructures. The thickness of WS NSs is ∼100 nm, while MoS 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 MoS. Additionally, the MoS NWs possess abundant lattice dislocations and vacancies in both Mo and S. The strong interfacial electron interactions between the WS core and MoS shell significantly enhance the catalytic activity for eNRR. As a result, the WS@MoS heterostructures achieve a high NH yield rate of 61.79 μg h cm and a Faradaic efficiency of 21.64% at -0.3 V vs RHE, surpassing that of both WS and MoS 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.