Transition Metal Carbide Core/Shell Nanoparticles by Ultra-Short Laser Ablation in Liquid.

Angela De Bonis,Agostino Galasso,Mariangela Curcio,Roberto Teghil,Antonio Santagata

doi:10.3390/nano10010145

Abstract

Transition metal carbide nanoparticles are a class of technological interesting materials with a wide range of applications. Among metal carbides, tantalum carbides have good compatibility with the biological environment while molybdenum carbides are used as catalyst in electrochemical reactions. Laser ablation of bulk transition metal targets in some liquids is here reported and laser ablation in organic solvents is used as simple synthetic strategy for the production of carbide nanostructures. Herein, the nanoparticles produced by ultra-short laser ablation of tantalum and molybdenum in water, acetone, ethanol and toluene have been characterized by TEM, XRD and XPS analysis. The combined effect of metal and solvent chemical and physical properties on the composition of the nanomaterials obtained has been pointed out. In particular, the different reactivity of Ta and Mo with respect to oxidizing species determines the composition of particles obtained in water, on the other hand the organic solvents decomposition allows to obtain transition metal carbide (TMC) nanoparticles. The observed carbonaceous shell formed on TMC allows to protect the particle’s carbidic core and to improve and tailor the applications of these nanomaterials.

Highlights

Transition metal carbides (TMC) have high melting point and good mechanical properties, usually
To understand the final composition of the NPs obtained by laser ablation in liquid, it is necessary to consider the mechanism of ultra-short laser interaction with a solid target confined in a liquid medium
We have studied the ultra-short laser ablation of Ta and Mo in water and organic solvents with different chemistry with the aim to highlight the combined effect of chemical properties of targets and solvents and of the reactions that take place in the laser induced cavitation bubble (CB) on nanoparticles composition

Summary

Introduction

Transition metal carbides (TMC) have high melting point and good mechanical properties, usually. The most commonly used method for the preparation of TMC is the carbonization of metal or metal oxide, this synthetic route requires long time and temperature over 1200 ◦C, usually [1]. Laser ablation in liquid (LAL) has been proposed as a valid option for the green synthesis of metallic, oxide and carbide NPs [7,8]. Carbon atoms and clusters can dissolve into transition metal nanoparticles allowing the formation of metal carbide structures. Complete knowledge of the ablation mechanism and the physic-chemical properties both of target materials both of solvents should be required to prepare nanomaterials with the desired composition

Methods

Results

Discussion

Conclusion