Review on the Synthesis Methods of Nano-Tungsten Oxide Dihydrate Colloid

Abstract

Tungsten being a transition element, forms oxide compounds of various oxidation states that enables it to form nanocolloids of tungsten oxide dihydrate. Multiple methods have been used in recent years to synthesize nano tungsten oxide dihydrate, including sol-gel synthesis, electrochemical deposition, hydrothermal synthesis and anodization. However, a universally accepted synthesis method for this material is not offered. The most appropriate method and its corresponding processing parameters for the synthesis of nano tungsten oxide dihydrate colloids were presented in the present study. The objective of the present study was to investigate the effect of processing parameters, i.e. applied voltage, temperature and anodizing duration on the particle size of nanocolloids. It is found that anodization is the easiest, efficient, and cost-effective method to synthesize the colloidal solution of nano tungsten oxide dihydrate. Conducting the synthesis at room temperature at a voltage of 50 V for 60 minutes yields the product with particle size of 40 – 60 nm, which can be used in wide array of applications. This paper also highlights the research gaps for future work and gives recommendations to extend this study particularly for the industrial application of tungsten oxide.

Effect of voltage and anodizing time on nano colloidal silver

“…According to the findings from Jaewoo et al [18], the particle size increases in diameter when there is an increase in voltage from 7.5 V to 12.5 V. Studies conducted by Javad et al [19] and Ahmet et al [20] have also resulted in a similar outcome where the particle size increases with the increase of voltage. Furthermore, the particle size increases with anodizing time until a certain point before decreasing [21]. This pattern be seen in Figure 3 where the particle size increases with anodizing time.…”

Solvothermal synthesis and characterization of monoclinic WO3 nanoplatelets: investigation of their photocatalytic performance

“…Numerous approaches can be used to create various WO3 morphologies. like Sol-Gel Synthesis [11] Electrochemical deposition [12] , hydrothermal [13] and solvothermale processes [14]. In terms of tungsten oxide nanoparticles, we can say that different morphologies have been obtained, Such as nanotubes [15][16][17] , nano-sheet [18] nanoplatelets [8,19] , quantum nanodot [5] and nano sphere [20], But among various nanostructures, two-dimensional inorganic nanomaterials have attracted considerable attention because they can open up new possibilities in the field of applied surface materials.…”

“…All generated reactive oxygen species (ROS) such as • OH and RhB *+ during the photocatalytic reactions suppress the recombination of the photoinduced electron-hole pairs and effectively decompose RhB into less toxic molecules or degraded or mineralized products Eq. (12)[61].RhB * + ( • OH and RhB •+ ) → degraded or mineralized products(12) …”