Biomorphic charcoal/TiO2 composites from poplar templates

Abstract

Biomorphic charcoal/TiO2 composites (C/TiO2) were produced from poplar templates. The poplar templates were impregnated with butyl titanate sol with a vacuum/positive pressure technology. From the anatomic structure of poplar and fluid thermodynamics, the alternative vacuum/positive pressure technology was an efficient method of infiltrating bio-templates with sol and overcoming the embolization effect of the sol in capillaries. After sol infiltration, the maximum density of the poplar was approximately 0.958 ± 0.005 g/cm3. Using X-ray diffraction (XRD), thermogravimetric data (TG-DTG), and scanning electron microscopy (SEM), it was found that the pore sizes in the cell walls of C/TiO2 were, respectively, 30 to 150, 3 to 15, and 1.5 μm, and a surprising mesoporous-like honeycomb structure formed at approximately 800 °C in a N2 atmosphere. The phase structure of C/TiO2 shifted from anatase to rutile between 700 and 900 °C in N2. Furthermore, the temperature of the maximum combustion rates of C/TiO2 sintered at 800 °C in N2 was approximately 610 °C. The average shrinkage values from the native poplar to C/TiO2 along the radial, tangential, and axial directions were 28.53%, 21.80%, and 17.03%, respectively.