In this work, Cu NPs were loaded at a fixed percentage (5 wt%) on 1D, (1D + 0D) and 0D ZnO nanostructures
to investigate the effect of the support morphology on the reduction of organic pollutants in water. The
synthesized materials were characterized by high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), X-ray
diffraction (XRD), N2 adsorption–desorption and X-ray photoelectron spectroscopy (XPS). The results
reveal that the loading of Cu NPs decreases the optical band gap, and a slight change in the crystallite
sizes increases the specific surface area value of the nanocomposites. The TEM images reveal that 1D
ZnO has an average width of 44.7 nm and an average length of 211 nm, while 0D ZnO has an average
diameter of 54.5 nm. The HR-TEM and XPS data confirm the loading of metallic Cu NPs on the surface
of the ZnO nanostructures. The pure ZnO and nanocomposites were tested for 4-nitrophenol (4-NP)
reduction in the presence of NaBH4 at room temperature. The obtained results show that pure ZnO
nanostructures have no catalytic performance, while the nanocomposites showed good catalytic
activities. The catalytic reduction efficiency of 4-NP was found to follow the order of Cu/0DZnO > Cu/
(1D + 0D)ZnO > Cu/1DZnO. The complete reduction of 4-NP has been observed to be achievable within
60 s using the Cu/0DZnO nanocomposite, with a kapp value of 8.42 min1 and good recyclability of up
to five cycles. This nanocomposite was then applied in the reduction of organic dyes in water; it was
found that the reduction rate constants for the methylene blue, Congo red, and acriflavine hydrochloride
dyes were 1.4 min1, 1.2 min1, and 3.81 min1, respectively. The high catalytic performance of this
nanocomposite may be due to the small particle size, high specific surface area, and the high dispersion
of Cu NPs on the surface of ZnO