Fabrication of Ag₂S/CdS Heterostructured Nanosheets via Self-Limited Cation Exchange

Abstract

Highly crystalline vertically aligned Ag2S/CdS heterostructured nanosheets with lateral sizes of several micrometers and thicknesses of a few nanometers are prepared directly on silver surfaces by a two-step process. Firstly, Ag2S sheets were prepared by direct reaction of partially dissolved elementary sulfur in methanol with a solid silver surface in methanol at room temperature. The second step involves a self-limited cation exchange of Ag+ vs. Cd2+ to achieve the formation of large-area Ag2S/CdS heteronanosheets on the solid substrate. The cation exchange was proven and investigated over time via several analytical methods, e.g. X-ray diffraction, Raman spectroscopy and three-dimensional photoluminescence mapping.

Effect of Cation Exchange Time on the Morphology and Photoactivity of CdS/Ag2S Composites for Ciprofloxacin Degradation

“…In 2018, Charlotte et al studied on CdS/Ag 2 S heterostructured nanosheets by the cation exchange for up to 5 days. [ 30 ] After 30 min reaction time, from XRD patterns, the cation exchange success was confirmed by the additional peaks which are in accordance with hexagonal CdS, and these peaks slightly increased with reaction time. The saturation of the cation exchange process was obtained after 5 days.…”

“…In another study, Charlotte et al noted that after 5 days of reaction time, the saturation of Cd 2+ versus Ag + was achieved. [ 30 ] Recently, Wang et al pronounced that the addition of hydrofluoric acid (HF) to the CE reaction accelerates the production of CdS/Ag 2 S composites. [ 13 ] However, the presence of HF easily causes the composite structural damage.…”