CHALLENGES IN THE SYNTHESIS OF COMPOSITES BASED ON HETEROPOLY COMPOUNDS
Published: 12 Sep 2020
Abstract: Polyoxometalates (POMs) are divided into two groups, namely isopoly and heteropoly anions. While the isopoly anions are built by (1) oxygen and (2) a transition metal (V, Nb, Ta, Mo, W), the heteropoly anions consist of: (1) oxygen atoms, (2) a metal labeled the addenda atom (W, Mo or V), and (3) an element generally from the p-block of the periodic table termed the heteroatom (Si, P or As). Heteropoly acids (HPAs) are composed of heteropoly anions and acidic hydrogen atoms. Among a wide variety of heteropoly acids, the Keggin type is the most stable and more readily available. Important characteristics responsible for a wide variety of applications of this type of compounds are: acidity, catalytic ability, easily and reversibly reduction in one- or multiple-electron steps, and significant biological activity. All these features are a consequence of their characteristic structure. The preparation of a composite material presents a complex experimental challenge. The combination of different components engineered in such a way that they preserve their useful properties could potentially enable a synergetic effect when investigated for a specific application. More than decade long investigations of our group from University of Belgrade try to find the answers whether the obtained composites would unify suitable properties of both components and improve: adsorption behavior for pesticide removal, antibacterial, and catalytic activity, as well as the charge storage properties. The basis of our work is the investigation of HPAs and their salts supported as an active phase on zeolites (H-BEA zeolite), mesoporous molecular sieves (TiO2, MCM-41, SBA-15), and carbon materials (active carbon, graphene oxide, HOPG). The results indicate that the interaction of HPAs with supporting materials is of substantial importance in applications and it has been studied in detail using different methods, such as the Fourier-transform infrared and Raman spectroscopy, X-ray photoelectron spectroscopy, temperature-programmed desorption method, zeta potential measurements, thermogravimetric-differential thermal analysis, X-ray diffraction analysis, transmission electron microscopy, and others.
Keywords: heteropoly compounds, keggin anion, composites, zeolites, carbon materials, mesoporous molecular sieves
Cite this article: Snežana M. Uskoković-Marković. CHALLENGES IN THE SYNTHESIS OF COMPOSITES BASED ON HETEROPOLY COMPOUNDS. Journal of International Scientific Publications: Materials, Methods & Technologies 14, 257-267 (2020). https://www.scientific-publications.net/en/article/1002068/
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