Sub-3 nm Ultrafine Cu₂ O for Visible Light Driven Nitrogen Fixation

Area of Science:

• Materials Science
• Photocatalysis
• Green Chemistry

Background:

• Copper(II) oxide (Cu2O) is a promising, cost-effective semiconductor photocatalyst for nitrogen (N2) reduction to ammonia (NH3).
• Thermodynamically feasible, visible light-driven N2 to NH3 conversion using Cu2O remains largely unexplored.

Purpose of the Study:

• To synthesize uniformly sized, ultrafine Cu2O platelets for efficient visible light-driven photocatalytic N2 reduction.
• To investigate the performance and stability of the synthesized Cu2O catalyst for NH3 synthesis.

Main Methods:

• In situ topotactic reduction of a Cu(II)-containing layered double hydroxide using ascorbic acid.
• Synthesis of ultrafine Cu2O platelets with lateral sizes less than 3 nm.
• Evaluation of photocatalytic activity under visible light (λ > 400 nm).

Main Results:

• Successfully synthesized uniformly sized, ultrafine Cu2O platelets (<3 nm).
• Achieved a high Cu2O-mass-normalized rate of 4.10 mmol g⁻¹ h⁻¹ for N2 to NH3 conversion under visible light.
• Demonstrated excellent catalytic performance and stability.

Conclusions:

• Ultrafine Cu2O platelets exhibit high efficiency for visible light-driven N2 photocatalytic reduction.
• High activity is attributed to long-lived photoexcited electrons in trap states, abundant active sites, and support structure.
• This research provides a foundation for designing advanced ultrafine catalysts for NH3 synthesis and other applications.