Preparation of Te(12 − x)/4PMo12 − xVxOn mixed oxides from heteropolycompound precursors for selective oxidation of isobutane

A series of Te(12 − x)/4PMo12 − xVxOn (x = 0–3) catalysts have been prepared from the corresponding heteropolycompound precursors and tested for the partial oxidation of isobutane. It has been found that Te(12 − x)/4PMo12 − xVxOm heteropolycompounds are more active than the corresponding mixed oxides, while similar activity can be obtained if higher reaction temperatures are used for mixed oxides (e.g. 390 °C). In addition, the selectivity to methacrolein increases remarkably over Te(12 − x)/4PMo12 − xVxOn (x = 0–3) mixed oxides compared with the corresponding heteropolycompound precursors. It is suggested that Te4 + in the mixed oxide system should play a key role for improvement of the catalytic behavior.

Graphical abstractFor Te(12 − x)/4PMo12 − xVxOm heteropolycompound catalysts (left), the conversion of isobutane and selectivity to MAA reaches a maximum when one vanadium is substituted to Mo atom in the molybdophosphoric system. However, for Te(12 − x)/4PMo12 − xVxOn mixed oxide system (right), the selectivity to MAL and MAA is gradually improved by the increase of V-content. In addition, the selectivities to MAL over Te(12 − x)/4PMo12 − xVxOn mixed oxides are generally higher than those over heteropolycompound catalysts at similar isobutane conversion.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Te(12 − x)/4PMo12 − xVxOn (x = 0–3) have been prepared for isobutane oxidation. ► Te element induced a positive effect on the selectivity to methacrolein. ► Te2.25PMo9V3On mixed oxide reached the best selectivity to methacrolein at 390 °C.