Bottom-up assembly to Ag nanoparticles embedded Nb-doped TiO2 nanobulks with improved n-type thermoelectric properties

Abstract

Nb-doped TiO 2-based nanostructures were novelly prepared by an economical and environmentally friendly hydrothermal method from TiO 2 and Nb 2 O 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 2 O 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 mV K À1 in the maximum case on account of the electron filtering effect. Moreover, their electrical conductivity (s) was also improved by one order of magnitude up to 160 U À1 cm À1 , resulting from the contribution of both introducing Ag nanoparticles and Nb-doping. Finally, the figure of merit (ZT) was increased by about twofold owing to the substantially optimized power factors (S 2 s). 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.

Refining nanotopographical features on bone implant surfaces by altering surface chemical compositions

“…Our results demonstrated that small amounts of Nb 2 O 5 does not affect the crystalline structures of the TiO 2 coatings as Nb is intercalated into the spaces between TiO 2 octahedron sheets during the coating process (solidication). [25][26][27] This intercalation resulted in shiing of the TiO 2 peaks to lower angles in the XRD pattern for the Nb 2 O 5 doped TiO 2 coatings (Fig. 1b and c).…”

High thermoelectric performance of all-oxide heterostructures with carrier double-barrier filtering effect

“…[25][26][27][28][29] Non-stoichiometry and doping can lead to a high-ZT value because of the enhancement of the Seebeck coefficient and electrical conductivity. However, non-stoichiometric TiO x (1oxo2) materials exhibit low thermal conductivity at high temperature.…”

Polymer based graphene/titanium dioxide nanocomposite (GTNC): an emerging and efficient thermoelectric material

“…For example, Xu et al 15 prepared Al-doped TiO2 nanostructured materials to increase the electrical conductivity and achieved an enhanced ZT of 0.091; Liu et al 16 reported that Ag-codoped TiO 2 nanostructured materials exhibit an enhanced ZT of 0.082 at 1073 K. In the past few decades, nanocomposites consisting of metal particles embedded in an insulating matrix have drawn great interest.…”