3D AgCl microstructures selectively fabricated via Cl−-induced precipitation from [Ag(NH3)2]+

Abstract

Herein various AgCl microstructures including octapods, octapods with fishbone pods, hexapods, hexapods with 4-blade arrowhead pods, concave octahedra, and octahedra are selectively precipitated from a [Ag(NH₃)₂]⁺ solution by addition of Cl⁻. The microstructures were rapidly formed and precipitated within 5 min. In a Cl⁻-rich environment, the octapod grew from cubic seeds as the growth along the 〈111〉 directions was favorable. The hexapod grew from octahedral seeds in an NH₄OH-rich environment as the growth along the 〈100〉 directions dominated. By manipulating the seed morphology and the growth environment, complex AgCl microstructures of thermodynamically unfavorable structures (hexapods and octahedra) can be selectively fabricated. A potential application of AgCl microstructures as photocatalysts was explored by partial photo-reduction of the surface AgCl into isolated AgNPs. The fabricated AgCl microstructures were turned into efficient Ag@AgCl visible-light photocatalysts as complete decomposition of methyl orange was achieved within 20 min. This work not only explores a method to control the preferential growth of AgCl microstructures along the 〈100〉 and 〈111〉 directions but also provides an in-depth understanding on the crystal growth mechanisms and how to manipulate them efficiently.