Quantum Chemical Analysis of the Processes of Synthesis of Vanadium Oxide Structures on the Silica Surface

摘要

Based on a combination of quantum chemical simulation and experimental studies, the formation of vanadium oxide structures on the silica surface when sequentially treated with VOCl(3)and H2O vapors was analyzed. The synthesis products were identified by IR spectroscopy. Changes in the composition and structure of the resultant surface species according to the process temperature and VOCl(3)vapor pressure in the reactor were predicted by quantum chemical methods. By the example of the synthesis at 473 K in a flow-through system and study of the chemical composition and structure of the new functional groups formed on the surface, a good agreement between the experimental and calculated data was demonstrated. The results of IR spectroscopic studies of the samples synthesized were processed using quantum chemical approaches. The characteristic IR absorption band due to vibrations of the bridging bonds of vanadium atoms with the Si-O-V matrix, localized at 920-945 or 960 cm(-1)depending on the structure of the surface sites, was used as the basis for identification of the surface vanadium oxide groups.