Chemical Reaction Pathways during Laser Fragmentation of Metallic Microparticles in Organic Solvents

Abstract

Laser synthesis and processing of colloids (LSPC) allows the scaled production of nanomaterials for applications in catalysis, biomedicine, and additive manufacturing. However, the processed raw material reacts with the solvent during nanoparticle formation, resulting in byproducts. Despite several studies on byproduct formation during LSPC in organic solvents, the reaction mechanisms are still unknown. To fill this knowledge gap, this study focuses on the microparticle laser fragmentation (MP-LFL) of four different metal microparticles in five different C₆ solvents in ambient and oxygen-depleted atmospheres. The influence of the solvent, metal, and dissolved oxygen on the gas formation rates, gas and liquid compositions, and nanoparticle properties is investigated. The gas and hydrogen formation rates were found to be dependent on the atmosphere and chemical properties of the solvent and metal. In contrast, the formation of liquid byproducts was independent of the metal and the atmosphere and is instead determined by the solvent. Based on this, solvent decomposition pathways during MP-LFL were proposed, providing general selection rules to suppress or enhance the formation of byproduct species.