Background:
Due to unique chemical and physical properties and potential application in
many fields, nanostructured materials have attracted many attentions. Cadmium sulfide (CdS) is a semiconductor
that has a wide band gap of 2.42 eV at room temperature and can be served in solar cells
and photoluminescence devices. Cadmium sulfide (CdS) is a kind of attractive semiconductor material,
and it is now widely used for optoelectronic applications. CdS nano and microstructures can be synthesized
via different chemical methods such as microwave-solvothermal synthesis, surfactant-ligand coassisting
solvothermal method and hydrothermal route. Also different morphologies of this semiconductor
such as dendrites, nanorods, sphere-like, flakes, nanowires, flower-like shape triangular and
hexagonal plates, were synthesized.
Methods:
To synthesis of the nanocomposite, a simple co-precipitation method was served. In briefly,
0.1 g of Pb(NO3)2 was dissolved in the distilled water (Solution 1). Also different aqueous solutions
were made from dissolving different mole ratio of Cd(NO3)2.6H2O respect to the lead source in the
water (Solution 2). Two solutions were mixed together under vigorous stirring and then S2- solution
(0.02 g thiourea in the water) was added to the Pb2+/Cd2+ solution. After that 0.1 g of CTAB as
surfactant was added to the final solution. Finally to the synthesis of both sulfide and oxide
nanostructures, NaOH solution was added to the prepared solution to obtain pH= 10. Distilled water
and absolute ethanol were used to wash the obtained precipitate and then it dried at 80 °C for 8 h.
Results:
From the XRD pattern it was found that the peaks placed at 24.9°, 27°, 44.1°, 48°, 52°, 54°,
57.8°, 66.8°, 71.2° are associated to CdS compound with hexagonal phase (JCPDS=00-001-0780) that
belong to (100), (002), (110), (103), (112), (201), (202), (203), (211) Miller indices respectively. The
Other peaks belong to PbS with hexagonal phase (JCPDS=01-078-1897), and CdO with cubic phase
(JCPDS=00-001-1049). From SEM images, it was found by choosing the mole ratio to 1:1, very small
and uniform particles were achieved. By increasing Pb2+/Cd2+ mole ratio to 1:2, very tiny particles aggregated
together were achieved.
Conclusion:
The results showed that the product can adsorb extra 80% of heavy metal ions from the
water. So it can be said that the nanocomposite can be used in the water treatment due to its high photocatalytic
and surface adsorption activities. In other words, it can remove heavy metals from the water
and also decompose organic pollutions.
Hybrid ZnO/MoS2 Core/Sheath Heterostructures for Photoelectrochemical Water Splitting
