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Updated: May 15, 2025

Ammonia Synthesis at Low Pressure
Published on: August 23, 2017
Light-driven directional decomposition of ammonia nitrogen coupled with proton migration for efficient hydrogen
Changqing Yang1, Xifei Zhou1, Wanli Li1
1School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China.
None:
The targeted construction of coupled systems, utilizing the unique features of combined photocatalytic redox reactions, is an effective strategy for enhancing catalytic performance. However, the hydrogen source in photocatalytic ammonia-nitrogen oxidation-coupled systems and the multi-electron proton migration pathways in such synergistic systems remain rarely studied. In this study, MoS2/UiOS-MCS composites were synthesized for the photocatalytic conversion of ammonia-nitrogen wastewater into hydrogen. The edge hydrogen evolution effect of MoS2 and the type-II heterojunction formed between both UiO-66-(SH)2 and MnCdS effectively facilitated the separation and transfer of photogenerated charge carriers. The composites exhibited a synergistic hydrogen production rate of 787.42 micromol g-1 h-1, 22 times higher than that of pure MCS, and the nitrogen selectivity is 99.05 %. In situ EPR and controlled experiments identified •NH2 as the intermediate product; Isotope tracing experiments revealed that the protons in hydrogen primarily originate from water, while protons from ammonia nitrogen are transported from the oxidation site to the reduction site. The mechanisms of ammonia nitrogen oxidation, proton transport pathways between reaction sites, and their contributions to hydrogen evolution were elucidated, and new insights were provided for designing photocatalytic synergistic systems and optimizing photocatalyst performance.
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