Reduction Of V2O5 Research Articles

Rhodium‐catalysed reduction of vanadium pentoxide and tungsten trioxide by hydrogen

AbstractHydrogen reduction of V2O5 and WO3 catalysed by rhodium, both in the pure form and supported on kieselguhr, has been studied. The products obtained at 300°C have been identified as VO2 and HxWO3. In situ electrical resistivity measurements on V2O5 pellets, both pure and admixed with the catalyst, show an anomalous resistance increase with temperature, perhaps arising from chemisorption and spillover of hydrogen from rhodium.

Thermal studies of the reactions of vanadium(V) oxide with other transition metal oxides

Studies of the thermal behaviour of binary oxide mixtures containing vanadium(V) oxide (V2O5-TiO2, V2,O5- MoO3, V2,O5-ZrO2 and V2O5-ZnO) have shown that the evolution of gaseous oxygen at fairly low temperatures is characteristic of those systems which are eflective catalysts for the oxidation of hydrocarbons. No weight changes were observed with V2, O5-ZnO mixtures under these conditions and, in accordance with this, zinc(II) oxide does not enhance the catalytic activity of vanadium(V) oxide. In V2O5-containing systems, evolution of oxygen occurs during the reduction of V2O5 to V2O4. This process is accelerated in the presence of certain metal oxides and such acceleration may be caused by structural interactions at the interface of the oxides. Among the systems studied, the formation of compounds such as Mo6V9O40 is thought to be of little significance from the catalytic point of view.

Structure and Catalytic Activity of V-Sn-W Oxide Catalyst for Butene Oxidation to Acetic Acid

Relationship between structure and catalytic activity of V-Sn-W oxide cata1yst for butene oxidation to acetic acid has been investigated bmeans of differential thermal analysis, IR-spectrometry, X-ray diffractometry and chemical analysis.An optimum calcination temperature of the catalyst is found to be between 450 and 500C, and the calcined catalyst was a mixture of each pure oxide. The contribution of SnO2 and WOs to the activity is ascribed to the promotion of reactivity of oxygen in V20s and to the increase of surface area of the catalyst, respectively. In the absence of oxygen, butene reduces only V2O5 in V-Sn-W oxide to form V4O9, and values of V5+/VTotal (VTotal=V5 V4+)ip the catalyst approach to 0.65 with, reaction time of the catalytic oxidation of butene. These results suggest that the activity of the catalyst is effectively increased when both V2O5and V40g coexist in the catalyst.Acidity of the catalyst has also been determined and found to be correlated with the extent of V2O5 reduction in the catalysts. The acidity is certainly responsible for the catalytic activity.

Electrorefining of vanadium prepared by carbothermic reduction of V2O5

Electrorefining of vanadium prepared by carbothermic reduction of V2O5