Sulfur-deficient Bi2S3−x synergistically coupling Ti3C2Tx-MXene for boosting electrocatalytic N2 reduction

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 Ti3C2Tx-MXene as an effective NRR catalyst. The developed Bi2S3 nanoparticles decorated Ti3C2Tx-MXene (Bi2S3−x/Ti3C2Tx) naturally contained abundant S-vacancies and exhibited a dramatically boosted NRR activity with an NH3 yield of 68.3 µg·h−1mg−1 (−0.6 V) and a Faradaic efficiency of 22.5% (−0.4 V), far superior to pure Bi2S3 and Ti3C2Tx, and surpassing almost all ever reported Bi- and MXene-based NRR catalysts. Theoretical investigations unveiled that the exceptional NRR activity of Bi2S3−x/Ti3C2Tx 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.