Abstract
Ammonia (NH(3)) is an important energy carrier and agricultural fertilizer. Development of electrocatalysts for efficient NH(3) electrosynthesis via the nitrate reduction reaction (NitRR) is highly desirable but remains a key challenge. In this work, we successfully loaded Au nanoparticles on BiVO(4) by a one-step hydrothermal method. It is demonstrated that by using Au nanoparticles (10-15 nm) embedded on BiVO(4) (Au/BiVO(4)) with oxygen vacancies (Au loading is 1.3 wt%), the electrocatalytic NitRR is indeed possible under ambient conditions. Unexpectedly, at -1.35 V (vs. RHE), the yield rate for NH(3) of Au/BiVO(4) reached 3320.9 ± 89.9 μg h(-1) cm(-2), which was far superior to (11.3 μg h(-1) cm(-2)) pristine BiVO(4). The (15)N isotope labeling experiments confirmed that the produced NH(3) indeed originated from the nitrate reduction reaction catalyzed by Au/BiVO(4). The comprehensive analysis further confirms that the oxygen vacancies in Au/BiVO(4) can effectively weaken the N-O bonding and restrain the formation of by-products, resulting in high faradaic efficiency and NH(3) selectivity. Furthermore, in situ differential electrochemical mass spectrometry (DEMS) was adopted to monitor the electrochemical separation of the NitRR products on the surface of Au/BiVO(4).