Controlled Synthesis of Semiconducting Metal Sulfide Nanowires

We describe the preparation and characterization of (a) discrete, individual motifs and (b) arrays of crystalline and pure semiconducting transition metal sulfide (CuS, PbS, and CdS) nanowires, synthesized via an inexpensive, generalizable, simplistic, and ambient modified template-directed technique. We have demonstrated control over the diameters and lengths of our one-dimensional (1-D) nanostructures through corresponding variations in the template membrane's pore size and thickness. We have not only successfully generated cubic-phase 1-D CdS nanowires but also produced, at slightly elevated temperatures, unusual CdS cactus-like, hierarchical nanostructures, consisting of tiny nanoneedles projecting out from the outer surfaces of parent CdS nanotube motifs. Opto-vibrational properties of all of these metal sulfide nanomaterials have been extensively studied. In addition, our results indicate that our as-prepared hexagonal-phase CdS cactus-like nanotubes evinced a higher photocatalytic degradation activity than that of both cubic CdS nanowires and their commercial bulk counterparts.