Abstract:
Herein, we report a unique single-step biogenic deposition precipitation (BDP) approach as
a straightforward route for producing efficient Schottky contact between noble metal nanoparticles and
wide-band-gap semiconductors. Successful preparation of Ag–ZnO heterojunctions using fennel seed
extract (FSE) has been described. The effective biomolecules available in the seeds functioned as novel
biogenic materials for the precipitation of adsorbed silver ions (Ag+) on ZnO particles as metallic silver
(Ag0
). The as-prepared composite materials were characterized using diffuse reflectance spectroscopy
(DRS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray
(EDX) study, X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL) and
high-resolution transmission electron microscopy (HR-TEM). The biogenically prepared Ag–ZnO
nanocomposites exhibited excellent photocatalytic activity towards reduction/degradation of colored
(rhodamine B (Rh-B) dye) as well as colorless (chlorpyrifos pesticide) pollutants when irradiated under
solar light. Among the prepared photocatalysts, 3 wt% Ag–ZnO hybrid composite showed the best
photocatalytic activity by efficiently degrading hazardous organic pollutants within a very short time. The
superior photocatalytic performance of biogenically prepared Ag–ZnO heterojunctions can be ascribed
to the clean production of steady and efficient Schottky contact between plasmonic AgNPs and
semiconducting ZnO NPs.
