Nanorods-assembled CeVO4 hollow spheres as active catalyst for oxidative dehydrogenation of propane

CeVO4 hollow sphere nanostructures have been prepared by a simple hydrothermal synthesis method. HRTEM investigation indicates that the CeVO4 hollow spheres are assembled by small single crystal nanorods. Through a plus post annealing treatment at 500 °C, the CeVO4 hollow spheres have more Ce4+ species (Ce4+/(Ce4+ + Ce3+) is ca. 5%) in the surface compared with the as-prepared sample (ca. 1%) based on the XPS results. No CeO2 and V2O5 phases were examined by both XRD and Raman spectroscopy, which indicates that Ce3+–Ce4+/V5+–V4+ coexist in the annealed CeVO4 hollow spheres, confirmed by the existence of V4+ detected by XPS. At 500 °C, the nanorods assembled CeVO4 hollow spheres exhibits a rather very high selectivity (ca. 70%) for propylene in oxidative dehydrogenation (ODH) reaction of propane. The presence of Ce4+, which induces additional V4+ in these hollow sphere nanostructures, is critical for the enhancement of selectivity of the catalyst.