Study of Photocatalytic Activity of Titanium and Tungsten Oxides Obtained by an Electric Explosion of Metal Conductors in the Air

Oxides in the form of micro- and nanosized powder, containing agglomerates of particles with a high specific surface, were obtained by means of electric Ti and W wire explosion in the air. An X-ray phase analysis showed that the only product of Ti destruction is TiO₂, while the electric explosion of W conductors results in the formation of WO₃ + W₂O₇ mixture, in which tungsten anhydride WO₃ dominates, and traces of a residual metallic W come across. The photocatalytic properties of electroexplosive powder were studied using a model oxidation reaction of methylene blue. It was revealed that both TiO₂ and the WO₃ + W₂O₇ mixture demonstrate catalytic activity within a wide spectrum of radiation, including the visible one. The catalytic activity of the WO₃ + W₂O₇ mixture under ultraviolet and incandescent lamp radiation was inferior to that of TiO₂; however, in the solar radiation, the rate of dye degradation with the participation of tungsten oxides is higher. In this case, the average rate of decreasing concentration of the dye in water containing a mixture of WO₃ + W₂O₇ depends little upon the type of the radiation source.