Pure and cerium-doped ZnO nanorods grown on reticulated Al2O3 substrate for photocatalytic degradation of Acid Red 88 azo dye

Pure and Ce-doped ZnO photocatalyst nanorods were both grown on α-Al 2 O 3 ceramic foams manufactured using a polymeric sponge replication technique. A three-dimensional network of α- Al 2 O 3 struts which served as the substrate for the photocatalyst material was first seeded via dip coating. The seed-mediated synthesis of ZnO nanorods with controlled lengths and diameters was then carried out at low temperature (∼95 °C) by chemical bath deposition (CBD). Their morphologies and crystallographic orientations were verified using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The effect of Ce-doping on the optical properties of the ZnO nanorods was investigated by ultraviolet–visible (UV–Vis) and photoluminescence (PL) spectroscopies. There was a modification in the band-gap structure with the incorporation of cerium atoms in the ZnO matrix as observed by the partial redshift at the absorption edges and by the blue and green light emissions. Color removal efficiencies of the samples were evaluated under UVA and visible light irradiations over the photocatalytic degradation of Acid Red 88 (AR88) azo dye molecules dissolved in water. Enhanced degradation rates were achieved for the Ce-doped samples compared to those of the pure ones. Similarly, the extend of mineralization (i.e., total organic carbon (TOC) removal) reached the maximum value of 54% for the Ce-doped samples under UVA light. According to the scavenging experiment results, it was found that the most effective radical involved in the present photocatalytic degradation reactions was the superoxide anion ( · O 2 − ). • CBD of pure and Ce-doped ZnO nanorod photocatalysts on the seed coated reticulated Al 2 O 3 substrates were carried out. • The reticulated structure provided a relatively high surface area in comparison to similar masses of bulk. • More adsorption and catalytic sites were available for the removal of the AR88 azo dye molecules dissolved in water. • Enhanced photocatalytic efficiencies with Ce-doping were attributed to the formation of and defects.