Chemical Conversions within the Mo-Ga-C System: Layered Solids with Variable Ga Content

Area of Science:

• Materials Science
• Solid-State Chemistry
• Nanomaterials

Background:

• Layered carbides, such as MAX phases, exhibit diverse properties but are challenging to synthesize.
• Mo₂Ga₂C is a unique 221 MAX phase with potential for tunable composition.
• Existing synthesis methods for MAX phases are often limited.

Purpose of the Study:

• To explore the variable gallium content in Mo₂Ga₂C.
• To demonstrate novel chemical pathways for synthesizing modified layered carbides.
• To investigate the structural and chemical stability of these new materials.

Main Methods:

• Chemical treatment of Mo₂Ga₂C with Lewis acids and CuCl₂.
• Powder X-ray diffraction (PXRD) for structural analysis.
• Electron microscopy and X-ray spectroscopy for material characterization.
• Density functional theory (DFT) calculations for theoretical validation.

Main Results:

• Selective removal of one Ga layer from Mo₂Ga₂C to form Mo₂GaC (211 MAX phase).
• Synthesis of Mo₂Ga_1-xCu_xC by Ga replacement with Cu, maintaining the hexagonal structure.
• Reversibility of the reaction, recovering Mo₂Ga₂C from Mo₂GaC.
• All synthesized phases crystallize in the hexagonal P6₃/mmc space group.

Conclusions:

• Novel synthetic routes enable controlled modification of layered Mo-Ga-C compounds.
• Tunable Ga content and partial substitution with Cu offer new avenues for materials design.
• The established hexagonal structure is robust across these compositional variations.