Potassium-stabilized metastable carbides and chalcogenides via surface chemical potential modulation

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Metastable carbides and chalcogenides offer significant application potential but suffer from instability, hindering synthesis and durability.
• Developing facile and controllable methods for synthesizing and stabilizing these materials remains a critical challenge in materials science.

Purpose of the Study:

• To develop a general and scalable strategy for the controllable synthesis and stabilization of metastable carbides and chalcogenides.
• To investigate the role of potassium ions in enhancing the synthesis and stability of metastable epsilon-iron carbide (ɛ-Fe2C).

Main Methods:

• Theoretical prediction and experimental validation of potassium ion (K+) influence on carbon chemical potential (μC) during synthesis.
• Utilized an iron nitride (Fe2N) precursor for the synthesis of metastable ɛ-Fe2C.
• Extended the methodology to synthesize various other metastable compounds including MoC, MoN, and MoS2/MoSe2 derivatives.

Main Results:

• Potassium ions were shown to enhance surface carbon chemical potential, facilitating controlled synthesis and improving the stability of metastable ɛ-Fe2C.
• Gram-level scalable ɛ-Fe2C demonstrated remarkable stability, lasting over 398 days in air, and excellent olefin selectivity and durability (>36 hours).
• The strategy proved versatile, enabling the synthesis of diverse metastable carbides and chalcogenides.

Conclusions:

• A facile, scalable, and general strategy for synthesizing and stabilizing metastable carbides and chalcogenides has been established.
• This approach effectively addresses the long-standing challenges of synthetic difficulty and poor durability associated with metastable materials.
• The developed method opens new avenues for the practical application of these promising materials.