Abstract
This article presents the bio-inspired synthesis of TiO2 using eggshell membranes (ESM) as a biotemplate
on which the crystals of TiO2 are nucleated and grown. The microstructure, phase transformations and
optical behavior were studied with the objective of understanding the effects of the thermal treatment
on the properties of the TiO2 powder for application in dye sensitized solar cells (DSSC). The technique
used for the mimetization of the ESM consists of submerging the biotemplate in an alcoholic solution of
TiCl4 and thermal treating the samples at 600, 700 and 800 8C. Thermal analysis (DTA and TGA) was used
to investigate the thermal decomposition of the membranes. X-ray diffraction (XRD) studies revealed the
phase evolution and the average crystal sizes. Scanning and transition electron microscopy (SEM and
TEM, respectively) were used to investigate the morphology of the obtained powders. UVvis diffuse
reflectance was used to investigate the optical properties. The porosity was also evaluated using a BET
instrument. The results indicated that the best features for DSSC application were presented by the
sample that was thermally treated at 600 8C. This is reflected in the good replication of the morphology of
the used biotemplate, with a nanocrystalline anatase phase (average crystal size 15.82 nm), high surface
area (64.8 m2/g), mesoporous structure (average pore size of 26.31 A˚ ) and large band gap (3.31 eV).
