Stabilising Gallium-based Liquid Metal Alloy Nanoparticles by Carbon Encapsulation

Abstract

Gallium-based liquid metal (LM) nanoparticles hold an exceptional promise for catalysis, energy storage, and printed electronics due to their high conductivity, fluidity, and dynamic catalytic surfaces. However, maintaining their mechanical and chemical stability remains a major challenge, as LM nanoparticles tend to agglomerate due to their high surface tension and are susceptible to chemical degradation, such as dissolution or leaching in reactive environments. Surface modification and encapsulation techniques are employed to enhance the mechanical and functional stability of these particles. Previously, methane pyrolysis has been considered as a route to produce high-purity hydrogen and carbon. In this work, we adopt methane pyrolysis as a novel strategy to form protective carbon shells around Ga-based alloy nanoparticles (NPs), providing mechanical confinement to prevent agglomeration and chemical shielding against corrosion and leaching. These carbon-encapsulated LM NPs retain catalytic activity while demonstrating improved mechanical and chemical robustness during high-temperature reactions. More importantly, by introducing different metals into Ga NPs, the catalytic activity and stability of the alloy NPs can be tuned by modifying elemental interactions, highlighting the advantages of ternary alloy NPs. This study introduces a new concept of using carbon shell formation to stabilise LM NPs, addressing key stability challenges while advancing their application in catalytic methane pyrolysis and multifunctional nanomaterials.