CdS structures prepared in AAO nanochannels via different synthesis methods under limited conditions

Nanomaterials have been widely used in the fields of photocatalysis, sensors, and solar cells due to their excellent properties. However, nanomaterials are mainly prepared under nonlimited conditions. With the development of biomimetic nanochannels, their gating properties and chemical stability have come to the fore. Inspired by the potential applications of biomimetic nanochannels, it is significant to synthesize nanomaterials inside biomimetic nanochannels under limited conditions for facilitating newer applications. Therefore, we used an anodic aluminum oxide (AAO) template with different pore diameters as the limited condition to synthesize CdS structures via different synthesis methods. We successfully synthesized CdS nanoparticles and flower-like CdS structures in AAO nanochannels by the electrochemical-assisted method or solution impregnation method. Field-emission scanning electron microscope (FESEM) results revealed that the CdS nanoparticles would agglomerate together to form irregular bulks with an increase in the applied voltage; flower-like CdS structures would block the AAO nanochannels for longer reaction times and higher concentrations. Energy-dispersive spectrometer (EDS) and X-ray diffraction (XRD) results revealed that these structures self-assembled into AAO nanochannels were, in fact, CdS. In conclusion, these methods can provide important guidelines for nanomaterial synthesis in AAO nanochannels.