Hydrothermal Synthesis and Photocatalytic Prореrties of Iron-Doped Tungsten Oxide

Substitutional solid solutions of the general formula h-W1–xFexO3, where 0.01 ≤ x ≤ 0.06, crystallizing in the hexagonal system based on h-WO3, were obtained using the hydrothermal synthesis method. It was shown that the crystal lattice of the synthesized compounds h-W1–xFexO3 is stabilized by NH4+cations in hexagonal channels. Using quantum chemical calculations, it has been proven that doping with iron is realized by replacing cations in the tungsten sublattice, and not by intercalation into lattice channels. In this case, the dopant is not an independent participant in reactions involving h-W1–xFexO3, causing only the reorganization of the near-Fermi states of the h-WO3 matrix. It has been established that the region of solid solution homogeneity with respect to the dopant ion is determined by the pH of the working solution. The largest specific surface area, equal to 108 m2/g, has h-W0.94Fe0.06O3, synthesized at pH 2.3. Its photoactivity when applied to 1,2,4-trichlorobenzene is several times higher than that of m-W0.94Fe0.06O3.