Defect-Mediated Catalysis for Low-Temperature Formation of Graphene-Based Materials.

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Low-temperature synthesis of graphene remains a significant challenge in materials chemistry.
• Existing methods often require high temperatures or complex precursors.

Purpose of the Study:

• To reveal a defect-mediated catalytic mechanism for low-temperature graphene formation.
• To demonstrate control over carbon nanostructure dimensionality via defect chemistry.

Main Methods:

• Utilized ceria (CeO₂) with dynamically generated oxygen vacancies.
• Employed acetylene (C₂H₂) as the carbon source.
• Combined *in situ* spectroscopy, thermogravimetry, and density functional theory (DFT) for mechanistic studies.

Main Results:

• Acetylene decomposition and carbon nucleation occurred at temperatures as low as 113 °C.
• Graphene domains formed below 300 °C.
• Temperature-dependent evolution from graphene quantum dots (300 °C) to porous graphene frameworks (600 °C) was observed.
• Identified a transition from radical to carbene pathway governed by CeO₂ oxygen-vacancy chemistry.

Conclusions:

• Established a defect-mediated catalytic paradigm for low-temperature graphene synthesis.
• Coupled oxide redox dynamics with carbon dimensionality control.
• Offered a general principle for producing graphene-based sp² carbon materials at low temperatures.