Hollow flower-like Cr2V4O13 hierarchical micro-nano architectures: Controlled self-assembly synthesis and the outstanding catalytic performances for ammoxidation of chlorotoluenes

The controlled synthesis of hierarchical micro-nano materials has attracted great interest due to their wide applications in catalysis and many other fields. In this paper, hollow flower-like Cr2V4O13 hierarchical micro-nano structures were successfully synthesized via a facile hydrothermal process and subsequent calcination treatment. The samples were characterized by XRD, TGA, FT-IR, SEM, TEM, XPS, TPR and N2 adsorption-desorption. SEM and TEM micrographs showed that the as-obtained Cr2V4O13 had a three-dimensional (3-D) hollow flower-like superstructure assembled by numerous nanoflakes with widths of 0.2 µm and thickness of about 30 nm. The micro-nano structured Cr2V4O13 exhibited high activity and selectivity in continuous ammoxidation of chlorotoluenes to the corresponding chlorobenzonitriles. To the best of our knowledge, this is the highest activity reported for selective ammoxidation of chlorotoluenes with Cr-V-O binary catalysts. The unique catalytic behavior of Cr2V4O13 was ascribed to the micro-nano hierarchical architecture and the increased active surface sites.