Pilot-scale synthesis of metal nanoparticles by high-speed pulsed laser ablation in liquids

Abstract

The synthesis of catalysis-relevant nanoparticles such as platinum and gold is demonstrated with productivities of 4 g h(-1) for pulsed laser ablation in liquids (PLAL). The major drawback of low productivity of PLAL is overcome by utilizing a novel ultrafast high-repetition rate laser system combined with a polygon scanner that reaches scanning speeds up to 500 m s(-1). This high scanning speed is exploited to spatially bypass the laser-induced cavitation bubbles at MHz-repetition rates resulting in an increase of the applicable, ablation-effective, repetition rate for PLAL by two orders of magnitude. The particle size, morphology and oxidation state of fully automated synthesized colloids are analyzed while the ablation mechanisms are studied for different laser fluences, repetition rates, interpulse distances, ablation times, volumetric flow rates and focus positions. It is found that at high scanning speeds and high repetition rate PLAL the ablation process is stable in crystallite size and decoupled from shielding and liquid effects that conventionally occur during low-speed PLAL.

Ultrasmall Yttrium Iron Garnet Nanoparticles with High Coercivity at Low Temperature Synthesized by Laser Ablation and Fragmentation of Pressed Powders

“…The highest productivity for PLAL, before the recent studies by Streubel et al, [21,22] was demonstrated by Saijti et al [23] They reported ap roductivity of 1.3 gh À1 for the PLAL-synthesis of Al 2 O 3 nanoparticles. Especially in the context of catalysis, it is important to be able to synthesize larger amountsofnanoparticles within areasonable amount of time.…”

Germanium Sub-Microspheres Synthesized by Picosecond Pulsed Laser Melting in Liquids: Educt Size Effects

“…Higher repetition rates, in turn, increase the amount of pulses interacting with a single particle in the liquid jet and lead to a faster processing. Similar to incubation effects observed during LAL with MHz lasers56, high-repetition rate LML might also benefit from incubation.…”

“…and significant contributions of Mafuné et al 34. on laser ablation in liquid (LAL), LAL has been demonstrated to be a scalable56 method for microparticle and nanoparticle synthesis that allows precise size control of the synthesized colloidal nanoparticles over a wide range from several micrometers7 to ~1 nanometer8. Due to applicability to most elements of the periodic table9, LAL is suited to produce a large variety of nanomaterials, including elemental particles10, oxides11, carbides12 as well as nanoalloy particles131415, nanoparticle-polymer composites161718, doped and undoped phosphor NPs19 and magnetic-chains2021.…”

Process Chain for the Fabrication of Nanoparticle Polymer Composites by Laser Ablation Synthesis

“…Nevertheless, the productivity, in general, was still very low, ranging within 5-20 mg h -1 for an actual one-hour long ablation [47]. Recent advances in ultrafast laser technology and optics, namely a new ultrafast high-power laser source and the invention of polygon scanners with high lateral scanning speed, allowed continuous nanoparticle productivities on the gram scale [21,48].…”