Fabrication of superhydrophobic (ZnO–CdS) nanocomposite coating with photocatalytic property

In this study ZnO nanostructures (NSs), CdS nanoparticles (NPs), and ZnO–CdS nanocomposites utilizing simple and affordable technologies were used to fabricate a coating with superhydrophobicity and photocatalytic activity following stearic acid (SA) modification for water pollution treatment. The higher hierarchical (micro-nano) structure increased the water contact angle (WCA) value from 56.6° and 20° for the substrates to 143 ± 2° when the composite nanomaterial was deposited, while it reached the value of 153 ± 3°, which indicates the superhydrophobicity coating formation. XRD, FE-SEM, Fourier transform infrared (FTIR), EDS, and UV–Vis spectroscopy were used to study the nanomaterial’s and superhydrophobic coatings, and the water contact angle was determined to assess wettability. X-ray diffraction revealed that the polycrystalline ZnO–CdS nanocomposite comprises the hexagonal wurtzite phase together with the hexagonal phase of ZnO and CdS. Pure ZnO has a 3.4 eV band gap, whereas CdS has band gap of 2.55 eV. The ZnO–CdS nanocomposite was utilized to test methylene blue (MB) dye photodegradation under visible light before and after SA treatment. After 90 min. of irradiation, the pure nanocomposite photodegraded 90% of the MB and 85% of the superhydrophobic (ZnO–CdS) coating.