Mechanistic Inquisition on the Reduction of C₁₇Si(NH₂)₂ to NH₃: A DFT Study

Area of Science:

• Materials Chemistry
• Catalysis
• Inorganic Chemistry

Background:

• Recent studies reported the activation of molecular nitrogen (N2) by silicon-substituted cyclo[18]carbon.
• This precursor, C17Si-(NH2)2, showed potential for ammonia (NH3) synthesis.

Purpose of the Study:

• To investigate the feasibility of NH3 formation through the addition of molecular hydrogen (H2) to the established precursor system.
• To explore the catalytic cycle and self-regeneration mechanism for continuous NH3 production.

Main Methods:

• Gaseous reaction media experiments involving silicon-substituted cyclo[18]carbon, N2, and H2.
• In situ analysis to monitor reaction intermediates and byproduct formation.
• Characterization of the catalytic cycle for ammonia synthesis.

Main Results:

• The addition of two moles of H2 to the precursor yielded two molecules of NH3 and a C17Si-H2 byproduct.
• An in situ reaction between unreacted C17Si-N2 and the C17Si-H2 byproduct regenerated the catalyst.
• The regeneration process formed a C17Si-(NH)2 adduct, restarting the catalytic cycle.

Conclusions:

• The silicon-substituted cyclo[18]carbon system effectively catalyzes NH3 production from N2 and H2.
• The catalyst demonstrates self-regeneration through in situ byproduct reactions, establishing a sustainable catalytic cycle.
• This finding opens avenues for efficient and continuous ammonia synthesis using novel carbon-based materials.