Electrocatalytic nitrogen reduction reaction (NRR) is an appealing route for the sustainable NH₃ synthesis, while developing efficient and durable NRR catalysts remains at the heart of achieving high-efficiency N₂-to-NH₃ electrocatalysis. Herein, we rationally combine vacancy and interface engineering to design sulfur-deficient Bi₂S₃ nanoparticles decorated Ti₃C₂T_x-MXene as an effective NRR catalyst. The developed Bi₂S₃ nanoparticles decorated Ti₃C₂T_x-MXene (Bi₂S_3-x/Ti₃C₂T_x) naturally contained abundant S-vacancies and exhibited a dramatically boosted NRR activity with an NH₃ yield of 68.3 μg·h⁻¹·mg⁻¹ (−0.6 V) and a Faradaic efficiency of 22.5% (−0.4 V), far superior to pure Bi₂S₃ and Ti₃C₂T_x, and surpassing almost all ever reported Bi- and MXene-based NRR catalysts. Theoretical investigations unveiled that the exceptional NRR activity of Bi₂S_3-x/Ti₃C₂T_x stemmed from its dual-active-center system involving both S-vacancies and interfacial-Bi sites, which could synergistically promote N₂ adsorption and *N₂H formation to result in an energetic-favorable NRR process.

Electrocatalytic N₂ reduction reaction (NRR) represents an appealing solution for sustainable ammonia production, whereas exploring high-efficiency NRR catalysts is highly desired but extremely challenging. Herein, we combine Ti₃C₂T_x-MXene quantum dots (MQDs) with porous Cu nanosheets to design a novel heterostructured MQDs/Cu as an effective and durable NRR catalyst. Impressively, MQDs/Cu showed a synergistically enhanced NRR activity with an NH₃ yield of 78.5 μg h⁻¹ mg⁻¹ (−0.5 Ⅴ) and a Faradaic efficiency of 21.3% (−0.4 Ⅴ), far superior to pure MQDs and Cu, and outperforming the majority of the state-of-the-art NRR catalysts. Density function theory computations demonstrated that the synergy of MQDs and Cu enabled the creation of interfacial Cu-Ti dimer as dual-active-centers to strongly activate the absorbed N₂ and promote the *N₂H formation, consequently resulting in the much reduced energy barriers and greatly enhanced NRR performance.

Electrocatalytic N₂ fixation through N₂ reduction reaction (NRR) has been regarded as a promising route for sustainable NH₃ synthesis, while exploring high-performing NRR catalysts is pivotal yet challenging. Herein, BN quantum dots/Ti₃C₂T_x-MXene (BNQDs/Ti₃C₂T_x) heterostructure is demonstrated as an efficient and durable NRR catalyst, exhibiting a high NH₃ yield of 52.8 ± 3.3 μg h⁻¹ mg⁻¹ with an FE of 19.1 ± 1.6% at −0.4 V (vs. RHE), which stand at the high level among all reported BN- and MXene-based NRR catalysts. Theoretical computations reveal that the electronic interactions between BNQDs and Ti₃C₂T_x enrich the electron density of B atoms at the heterointerface and endow them with enhanced electron-donating capability for N₂ activation and protonation. Meanwhile, the decorated BNQDs can block the active sites of Ti₃C₂T_x for hydrogen evolution, rendering a high N₂-to-NH₃ selectivity.