Visible-Light-Driven Ammonia Photosynthesis on Mo₇-Cluster Stabilized CeO₂ Nanocore Through Interfacial Charge...

Area of Science:

• Materials Science
• Catalysis
• Photochemistry

Background:

• Developing efficient photocatalysts for sustainable ammonia synthesis is crucial.
• Nitrate reduction to ammonia offers a promising route for nitrogen fixation.
• Controlling interfacial charge transfer is key to enhancing photocatalytic performance.

Purpose of the Study:

• To stabilize a vacancy-rich cerium dioxide (CeO2) nanocore using a [Mo7O24]6- cluster for enhanced photocatalysis.
• To investigate the interfacial charge transfer dynamics in the Mo7@CeO2 heterostructure for nitrate photoreduction.
• To demonstrate a potential strategy for solar-driven ammonia photosynthesis using wastewater.

Main Methods:

• Synthesis of Mo7@CeO2 nanocore with high aqueous dispersity and pH stability.
• Advanced spectroscopic techniques including in situ EPR, fs-TAS, and in situ KPFM to probe interfacial charge transfer.
• Computational studies to understand internal electric field formation and charge localization.
• 15N-labeling, pH-variation, and D-labeling studies to confirm reaction pathways.

Main Results:

• Covalent connectivity between Mo7 clusters and CeO2 nanocore was established.
• The type-II heterostructure facilitated efficient exciton separation and prolonged charge carrier lifetime.
• High yield rate of ammonia photosynthesis (>95% selectivity, ~332 mg h-1) was achieved.
• Computational and experimental studies revealed internal electric field formation and charge localization.

Conclusions:

• The inorganic Mo7 ligand plays a pivotal role in regulating CeO2 core size, band alignment, and charge transfer dynamics.
• The Mo7@CeO2 heterostructure is a promising platform for efficient solar-driven ammonia photosynthesis.
• This strategy offers a sustainable approach for ammonia production from nitrate-containing wastewater.