Nb-doped TiO 2-based nanostructures were novelly prepared by an economical and environmentally friendly hydrothermal method from TiO 2 and Nb 2O 5 powder precursors. The proposed formation mechanism is acceptable for the design of various Nb-doped TiO 2-based nanostructures. Furthermore, Nb-doped TiO 2 nanostructured bulk materials (nanobulks) embedded with Ag nanoinclusions were first fabricated by the bottom-up assembly of Ag 2O nanoparticles loaded Nb-doped TiO 2-based nanostructures. The introduction of Ag nanoparticles remarkably increased the Seebeck coefficient (S) of the TiO 2 bulk ceramic by 15% to 370 μV K -1 in the maximum case on account of the electron filtering effect. Moreover, their electrical conductivity (σ) was also improved by one order of magnitude up to 160 Ω -1 cm -1, resulting from the contribution of both introducing Ag nanoparticles and Nb-doping. Finally, the figure of merit (ZT) was increased by about two-fold owing to the substantially optimized power factors (S 2σ). Our obtained results strongly confirm that the Ag embedded Nb-doped TiO 2 nanobulks can be used as good thermoelectric materials up to the high temperature of about 800 °C.
ASJC Scopus subject areas
- Materials Chemistry