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Abstract: Hollow cerium dioxide structures (HCSs) were prepared by a simple manufacturing method using Ceiba pentandra (L.) Gaertn. (kapok) fibers as a natural biomass template. The heat decomposition of the kapok template and the subsequent formation of a nanocrystalline phase of CeO2 in HCSs were studied by thermal gravimetric analysis and X-ray diffraction. The uniform morphology of the obtained HCSs with a diameter of 10–15μm was investigated by field-emission scanning electron microscopy. Despite the micrometer size of the HCSs, the walls had a high specific surface area and mesopores that were well developed, as determined by N2 gas adsorption–desorption analysis. Further, X-ray diffraction analysis revealed that the formation of HCSs was largely influenced by the calcination temperature. [Copyright &y& Elsevier]

Abstract: Hollow TiO2 fibers with a high surface area were prepared by a simple manufacturing method using Ceiba pentandra (L.) Gaertn. (kapok) as a natural biomass template. Heat treatment was used for the removal of the kapok template. The uniform morphology of the hollow TiO2 fibers with an average diameter of 10μm was investigated by field emission scanning electron microscopy (FE-SEM). In spite of the micrometer size of the hollow TiO2 fibers, the walls had a high surface area (143m2/g) and a high pore volume (0.21cm3/g), as determined by Brunauer–Emmett–Teller (BET) analysis. Calcination was found to promote the crystalline transformation of TiO2, as evidenced by X-ray diffraction (XRD). [Copyright &y& Elsevier]