Synthesis and characterization of porous chromia-pillared layered lanthanum niobic acid

The first chromia-pillared layered lanthanum niobic acid was prepared by an ion-exchange route, in which n-hexylamine-pre-expanded lanthanum niobate reacted with chromium(III) acetate [Cr(OAc)3] aqueous solution under reflux condition, and the ion-exchanged product was calcined at 450 °C in air flow. The structure of the novel pillared material was examined by means of various analytical techniques, such as powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric and differential analysis (TG/DTA), nitrogen adsorption-desorption, and transmission electron micrographs (TEM). The chromia-pillared layered lanthanum niobic acid exhibited a porous layered structure with a BET (Brunauer-Emmett-Teller) surface area of 89 m2·g− 1 and an interlayer distance of 1.31 nm. The layered structure could be retained up to 550 °C.