Understanding the Solvent Molecules Induced Spontaneous Growth of Uncapped Tellurium Nanoparticles

Abstract

Understanding the thermodynamic behavior and growth kinetics of colloidal nanoparticles (NPs) is essential to synthesize materials with desirable structures and properties. In this paper, we present specific uncapped Te colloidal NPs obtained through laser ablation of Te in various protic or aprotic solvents. At ambient temperature and pressure, the uncapped Te NPs spontaneously exhibited analogous evolution and growth of “nanoparticle-nanochain-agglomerate-microsphere” in different solvents. The distinctive growth kinetics of the formation of nanochains strongly depended on the polarity and dielectric constant of solvent molecules. The growth rate of agglomerates and microspheres was closely related to the zeta potential of the colloidal solution of Te nanochains and the average size of Te agglomerates. Furthermore, the resulting uncapped Te NPs and Te nanochains displayed a prominent size-dependent and structure-inherited chemical reductive ability. These findings provide insights into the growth of active uncapped nanoparticles in various dispersion media. This study also provides an alternative route in designing novel nanostructures of alloys, telluride, and functional composites using Te as a unique reactive precursor.

Recent Advances in Surfactant‐Free, Surface‐Charged, and Defect‐Rich Catalysts Developed by Laser Ablation and Processing in Liquids

“…There are many possible growth routes for the tiny particles (<10 nm) to evolve into different nanostructures, as summarized in ref. , including LaMer‐like mechanism, reaction‐induced growth, adsorbate‐induced growth, coalescence, Ostwald ripening, particle attachment, self‐assembly, and self‐splitting . Owing to the large variety of plasma‐induced ions and atoms, nanomaterials such as metals, alloys, oxides, hydroxides, carbides, nitrides, and NP–polymer composites are achievable by LAL …”

“…Organic solvents, such as acetone and ethanol, have been widely used for LAL and LPL, in which case acetone enolate (Figure a) and alcoholate (Figure b) may adsorb on the NP surface, respectively. Organic solvent molecules may behave like surfactants to stabilize the synthesized NPs . Size quenching is often observed during LAL in organic solvents, yielding smaller particles sizes than those, for example, in water .…”

“…Oriented attachment and self‐assembly of the small particles can be triggered by the adsorption of organic molecules. As a consequence, tellurium NPs evolve into submicro‐ or microscale particles . Chemisorption, physisorption, and complexing adsorption may occur during LAL in organic solvents .…”

“…The growth rates of the small particles are correlated with the adsorbed species. The growth rate of tellurium NPs in water is much faster than those in organic solvents (CH 3 OH, CH 3 CH 2 OH, CH 3 COCH 3 , and CH 2 Cl 2 ) . Therefore, the preservation of the original states of the colloids has become a big challenge.…”

“…However, the surface charges are not usually strong enough to stabilize the particles for a long period (e.g., one week) . Particle coalescence, particle ripening, or particle assembly often take place and, as a consequence, the particle size significantly increases. Particle evolution is unfavorable for catalytic applications because, on one hand, it dramatically decreases the specific surface area of the catalysts; thus drastically reducing the active sites available for reactions.…”