Synthesis, Characterization, and Anti-Algal Activity of Molybdenum-Doped Metal Oxides

Abstract

In this study, we attempted to synthesize visible light active nano-sized photocatalysts using metal oxides such as zinc oxide, zirconium oxide, tungsten oxide, and strontium titanium oxide with (MoCl5)2 as a dopant by the simple ball-milling method. Fourier-transform infrared spectroscopy data confirmed the presence of M-O-Mo linkage (M = Zn, Zr, W, and SrTi) in all the molybdenum-doped metal oxides (MoMOs), but only MoZnO inhibited the growth of the bloom-forming Microcystis aeruginosa under visible light in a concentration-dependent manner up to 10 mg/L. Further, structural characterization of MoZnO using FESEM and XRD exhibited the formation of typical hexagonal wurtzite nanocrystals of approximately 4 nm. Hydroxyl radical (·OH), reactive oxygen species (ROS), and lipid peroxidation assays revealed ·OH generated by MoZnO under the visible light seemed to cause peroxidation of the lipid membrane of M. aeruginosa, which led to an upsurge of intracellular ROS and consequently introduced the agglomeration of cyanobacteria. These results demonstrated that nano-sized MoZnO photocatalyst can be easily synthesized in a cost-effective ball-mill method and utilized for biological applications such as the reduction of harmful algal blooms. Further, our study implies that a simple ball-milling method can provide an easy, green, and scalable route for the synthesis of visible light active doped metal oxides.

Microwave-Assisted Synthesis and Characterization of Solar-Light-Active Copper–Vanadium Oxide: Evaluation of Antialgal and Dye Degradation Activity

“…The increased fluorescence intensity of terephthalic acid in the presence of Cu-VO indicated the production of •OH in the medium. Additionally, to support this result, we performed the same experiment in the presence of isopropanol [56], a well-known •OH scavenger. The fluorescence intensity of the terephthalic acid was decreased in the presence of isopropanol, which supported our hypothesis.…”

“…The fluorescence intensity of the terephthalic acid was decreased in the presence of isopropanol, which supported our hypothesis. The presence of •OH in the algal medium induced oxidative stress in the algal cells [56]. The antitumor activity of vanadium dioxide nanocoated quartz glass was due to the induction of intracellular ROS [57,58].…”

“…where A i and A f are the absorbance value (λmax = 660 nm) of MB solution at time 0 and t min, respectively. •OH Assay •OH assay was performed using the same procedure as mentioned in our previous paper [56] with slight changes. The terephthalic acid solution was incubated with 4 mg/L of Cu-VO under natural solar light.…”

A Study on the Properties of Sodium Dodecyl Sulfate Surfactant-Assisted Zinc Oxide Thin Films Doped with Molybdenum

“…Introducing the dopant led to the elimination of the sticky surface morphology and resulted in long nanorods evenly distributed over the substrate surface. The nanorods obtained have been attributed to the inclusion of Mo as dopant [10]. Increasing the amount of Mo from 0.3 M to 0.5 M led to more agglomerations as seen in Figure 3(b).…”

“…Other structural parameters such as the lattice constants (a and c) and the lattice strain (ɛ) have also been determined and are listed in Table 1. The lattice strain could be attributed to the dopant introduced at the lattice sites of the host material and the different ionic radii of zinc and Mo [10]. As the crystallite size increases, the lattice constants decrease towards increasing 2theta values.…”