Cl−-Induced selective fabrication of 3D AgCl microcrystals by a one-pot synthesis method

Abstract

The controllable preparation of crystals is a prerequisite for exploring their shape-dependent physicochemical properties. Herein, AgCl crystals with different morphologies including octahedron, trapezohedron (TPH), 12-pod and hexapods with mace pods were successfully prepared by a one-pot synthesis method. In the preparation process, ethylene glycol (EG) was used as a solvent and AgNO₃ was used as a precursor of Ag⁺. In particular, the ionic liquid poly(diallyldimethylammonium chloride) (PDDA) not only acted as a Cl⁻ ion precursor but also as a morphology-controlled stabilizer. We further explored the effects of temperature, ligand and precursor concentration on AgCl crystal growth. Moreover, we investigated the effect of Cl⁻ concentration on the morphology of AgCl by adding different amounts of NaCl. We found that under the condition of the lower concentrations of Cl⁻, {111}-bound octahedral AgCl crystals will transform into TPH enclosed with the {311} facet as the concentration of Cl⁻ ions increases. However, at medium concentrations of Cl⁻, {111}-bound octahedral AgCl crystals will transform into 3D 12-pod AgCl crystals as the concentration of Cl⁻ ions increases. Under the condition of higher concentrations of Cl⁻, {111}-bound octahedral AgCl crystals will transform into hexapods with mace pods AgCl crystals as the concentration of Cl⁻ ions increases. According to the experimental results, we proposed the growth mechanism of AgCl microcrystals. This work not only provides a new method for the synthesis of AgCl crystals with a tunable shape, but also helps to understand the crystal growth mechanism.