Facile synthesis of tellurium nano- and microstructures by trace HCl in ionic liquids

Ionic liquids (ILs) are widely used as versatile solvents for the synthesis of nanomaterials. However, the effect of IL impurities on the formation of nanomaterials is often neglected. Herein, we report on the formation of tellurium (Te) nanoparticles from the reaction of trialkylphosphane tellurides, formed by reactive dissolution of Te in dried commercial trihexyltetradecylphosphonium chloride ([P₆₆₆₁₄]Cl) at high temperatures, with common polar protic solvents (e.g. water, alcohols, or amides). Highly homogeneous Te nano- and microstructures with various sizes and morphologies including three-dimensional (3D) Te fusiform assemblies and 3D aloe-like Te microarchitectures are obtained. Our investigation shows that trace amounts of HCl impurities in [P₆₆₆₁₄]Cl tend to remain as [P₆₆₆₁₄][HCl₂] due to the strong interaction with Cl^-. The addition of a polar, protic solvent liberates active HCl from the HCl₂^- anion which we found to play an essential role in the formation of Te particles due to the accelerating effect of P-Te bond cleavage. This approach presents a general and convenient synthetic strategy for the preparation of Te nano- and microstructures.