Optimizing the efficiency of MoVTeNbO catalysts for ethane oxidative dehydrogenation to ethylene

MoVTe(Sb)NbO catalysts have been prepared using the slurry method and tested as catalysts for the oxidative dehydrogenation of ethane. The influence of both the addition of silica to the starting slurry during the preparation and of a final heat treatment under nitrogen at 873 K after the dissolution of the M2 phase formed concomitantly to the active M1 active phase has been studied. While the parameters change the texture of the catalysts without modification of the catalytic sites, they have opposite effects on catalytic properties. The addition of silica increases the conversion without modifying the selectivity to ethylene and the final heat treatment decreases the conversion but increases the selectivity. These effects have been explained respectively by a decrease of the agglomeration and sintering of the M1 phase crystallites and a decrease of the number of small pores, where total oxidation takes place. These effects could be leveraged to optimize the preparation protocol and obtain more efficient catalysts for the oxidative dehydrogenation of ethane.

Graphical abstractAgglomeration of M1 phase crystallites with pores of various sizes formed by the M2 phase dissolution.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► SiO2 addition during preparation of M1 phase increases conversion in ODH of ethane. ► Heat treatment under N2 at 600 °C of M1 phase increases selectivity to ethylene. ► Combining addition of SiO2 and final heat treatment leads to very efficient catalysts.