Influence of different precursors on isobutene production from bio-ethanol over bifunctional Zn1Zr10Ox catalysts

The effects of zinc precursors on the performance of bifunctinal Zn 1 Zr 10 O x catalysts were investigated for direct conversion of bio-ethanol into isobutene (ETIB). The catalyst derived from zinc acetate precursor exhibited full ethanol conversion and 50% isobutene yield at a WHSV of 0.38 g ethanol  g cat −1  h −1 at 450 °C. Characterization results based on XRD, FT-IR, UV–vis, Raman, BET, CO 2 -TPD, NH 3 -TPD, H 2 -TPR, and XPS revealed that Zn 1 Zr 10 O x catalyst prepared by zinc acetate precursor with large anion size possessed the highest zinc dispersion and the strong ZnO-ZrO 2 interaction, and presented the highest ethanol reaction rate and isobutene yield under kinetic control regime. The beneficial effect of larger anion size was rationalized by the shielding effect in the incorporation model dominated by the size of capping anion in zinc precursors. Further durability test showed that the catalyst exhibited slow deactivation against coking formation while isobutene yield was maintained above 45% for 18 h.