Specific Ion Effects on Aggregation and Charging Properties of Boron Nitride Nanospheres.

Tímea Hegedűs,Zoltán Kónya,István Szilágyi,Lívia Vásárhelyi,Dóra Takács

doi:10.1021/acs.langmuir.0c03533

Tímea Hegedűs, Zoltán Kónya + Show 3 more

Open Access

https://doi.org/10.1021/acs.langmuir.0c03533

Copy DOI

Abstract

The charging and aggregation properties of boron nitride nanospheres (BNNSs) were investigated in the presence of electrolytes of different compositions and valences in aqueous suspensions. The influence of mono- and multivalent cations (counterions) and anions (coions) on the colloidal stability of the negatively charged particles was studied over a wide range of salt concentrations. For monovalent ions, similar trends were determined in the stability and charging of the particles irrespective of the salt composition, i.e., no ion-specific effects were observed. Once multivalent counterions were involved, the critical coagulation concentrations (CCCs) decreased with the valence in line with the direct Schulze–Hardy rule. The dependence indicated an intermediate charge density for BNNSs. The influence of the coions on the CCCs was weaker and the destabilization ability followed the inverse Schulze–Hardy rule. The predominant interparticle forces were identified as electrical double-layer repulsion and van der Waals attraction. These findings offer useful information to design stable BNNS dispersions in various applications, where mono- and multivalent electrolytes or their mixtures are present in the samples.

Highlights

Boron nitride (BN) is a widely studied inorganic nanomaterial; it exists in several crystalline forms.[1]
The synthesized BN nanospheres (BNNSs) were characterized by different techniques to verify the successful formation of the product and to define its morphological characteristics
All of the peaks can be attributed to the hexagonal BN, in agreement with that previously reported for h-BN.[38]

Summary

Introduction

Boron nitride (BN) is a widely studied inorganic nanomaterial; it exists in several crystalline forms.[1] Among them, hexagonal BN (h-BN) is of special interest since h-BN possesses a similar structure to graphene with alternating B and N atoms in a planar hexagonal lattice.[2] The B−N covalent bond, in contrast to the C−C bonds in graphene, manifests an ionic character owing to the electronegativity of the N atoms.[3] Twodimensional (2D) h-BN nanomaterials have been extensively studied in the past few years.[4] sheets of h-BN are able to stack into multilayers to form 3D nanostructures such as BN nanospheres (BNNSs)[5] or wrap into BN nanotubes (BNNTs).[6] These are promising materials; they show distinct electronic and optical properties compared to their isoelectronic counterpart.[7] Both BNNSs and BNNTs display outstanding features, such as high thermal stability and conductivity,[8] chemical inertness,[9] corrosion, and oxidation resistance.[10]

Methods

Results

Conclusion