Fabrication of NiSx/MoS2 interface for accelerated charge transfer with greatly improved electrocatalytic activity in nitrogen reduction to produce ammonia

Abstract

Electrocatalytic reduction of dinitrogen to produce ammonia at ambient conditions has increasingly attracted attentions. Molybdenum sulfide (MoS2) exhibits promises in electrocatalysis. However, the lack of reactive sites significantly limited the electrocatalytic activity of MoS2 when applied in the reduction of N2 to produce ammonia. Herein, we successfully prepared a NiSx/MoS2 heterostructural composite with abundant interfaces exposed. Moreover, the presence of metallic phase 1T-MoS2 provided better conductivity and more active sites. Benefited from this interface design, as-prepared NiSx/MoS2 composites exhibited excellent electrocatalytic activity in reduction of N2. The ammonia yield rate reached as high as 68.78 µg h−1 mg−1cat. at −0.60 V (vs. RHE) with a Faradic efficiency of 48.53 % at −0.50 V (vs. RHE), as well as charming selectivity and long-term stability. The density functional theory (DFT) calculation results indicated that the heterointerface formed between NiSx/MoS2 composites facilitated electrons transfer. And the adsorption of N2 on the Mo site is more stable, which synergistically improves the NRR performance. This work provides new evidences of constructing heterojunction materials to accelerate electron transfer between interfaces for highly efficient electrocatalytic nitrogen reduction.