Photochemical Acceleration of Ammonia Production by Pt

Area of Science:

• Materials Science
• Catalysis
• Green Chemistry

Background:

• Metal nitrides (MN) are key materials for future green ammonia production via the ammonia-hydrogen nexus.
• Reductive hydrogenation of MN to MN1-x is essential for ammonia generation but is hindered by stable M-NHx surface species.
• Current methods face challenges in achieving efficient reduction under mild conditions.

Purpose of the Study:

• To overcome the challenge of kinetically stable M-NHx species in metal nitride reduction.
• To develop a photochemical method for efficient ammonia synthesis from metal nitrides under mild conditions.
• To explore the role of supported platinum single atoms and clusters in this process.

Main Methods:

• Utilized titanium nitride (TiN) as the metal nitride material.
• Employed supported single atoms and clusters of platinum (Pt1-Ptn) under nitrogen-hydrogen (N2-H2) conditions.
• Investigated photochemical activation of TiN and the catalytic activity of Pt1-Ptn for ammonia formation.

Main Results:

• A photochemical approach using Pt1-Ptn on TiN successfully circumvented deleterious Ti-NHx accumulation.
• TiN photochemistry selectively promoted Ti-NH formation, while Pt1-Ptn efficiently converted it to ammonia.
• The primary source of generated ammonia was TiN reduction, with a minor contribution from N2 activation.

Conclusions:

• This study presents a novel photochemical strategy for efficient ammonia production from metal nitrides.
• The findings demonstrate the potential of supported platinum single atoms/clusters to enable mild-condition MN reduction.
• This work could pave the way for developing advanced metal nitride materials to disrupt the Haber-Bosch process.