Synergistic asymmetric B-Mo dual Lewis sites in boron-doped MoS2 nanoflowers enable efficient electrochemical nitrogen fixation

Boron doping activates MoS 2 basal planes and constructs B-Mo dual Lewis acid sites for NRR. • B-MoS 2 -5 delivers superior NRR performance of NH 3 yield of 22.1 μg mg -1 cat. h −1 , and a FE of 27.1%. • In-situ ATR-FTIR confirms B-Mo sites enhance N 2 activation and suppress HER. Ambient electrochemical nitrogen reduction reaction (NRR) powered by renewable electricity offers a sustainable alternative to the energy-intensive Haber-Bosch process. However, achieving efficient N≡N bond activation while suppressing the competing hydrogen evolution reaction (HER) in aqueous electrolytes remains a major challenge. Herein, we fabricated Boron-doped MoS 2 (B-MoS 2 ) nanoflowers with abundant asymmetric B-Mo Lewis acid sites as electrocatalysts for NRR. In 0.1 M Na 2 SO 4 , the optimized B-MoS 2 achieves an ammonia yield rate of 22.1 μg mg -1 cat. h −1 at −0.35 V vs. reversible hydrogen electrode (RHE) and faradaic efficiency (FE) of 27.1% at −0.3 V vs. RHE, outperforming most previous reports. The superior performance is attributed to the synergistic effect of the B-Mo dual Lewis acid sites: the electron-deficient B site enhances N 2 adsorption by capturing its lone-pair electrons, while Mo promotes π-backdonation to polarize and activate the N≡N bond. Simultaneously, the strong Lewis acidity of B suppresses H⁺ adsorption, inhibiting HER. In-situ electrochemical attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy further confirms B-Mo sites boost N 2 adsorption and activation, favoring NRR over HER. This work provides insights for the rational design of sustainable electrocatalysts for ambient nitrogen fixation. A phase-engineered boron-doped MoS 2 nanoflowers were synthesized for enhancing B-Mo dual-site accessibility and efficient electrochemical nitrogen fixation. Download: Download high-res image (144KB) Download: Download full-size image