Composites of Bi ₂ WO ₆ Quantum Dots and WO ₃ Nanosheets Rich in Oxygen Vacancies for N ₂ Electroreduction

The traditional Haber–Bosch ammonia synthesis process is expected to be replaced with a sustainable and green electrochemical ammonia synthesis method. However, the bond energy of nitrogen molecules is high, making them extremely difficult to decompose. Therefore, it is necessary to develop highly active electrocatalysts to accelerate the dissociation of nitrogen gas and efficiently synthesize ammonia. Herein, we report the development of the Bi2WO6 quantum dots/WO3 (Bi2WO6 QD/WO3). Their synergistic effect can effectively inhibit the competitive hydrogen evolution reaction, enhancing catalytic activity for NH3 synthesis. In 0.1 mol/L Na2SO4, compared with pure WO3, Bi2WO6 QD/WO3 achieve a higher Faradaic efficiency (FE) (10.1%) and a larger NH3 yield (43.5 μg h–1 mgcat–1) at −0.5 V. Meanwhile, Bi2WO6 QD-WO3 attain the lowest FEs of hydrogen evolution reaction (HER), further illustrating that Bi2WO6 QD-WO3 can effectively inhibit the HER. Theoretical calculations and experimental results indicate that the embedding of quantum dots can effectively regulate the concentration of oxygen vacancies, accelerate interface charge transfer, and improve nitrogen reduction reaction performance.