Abstract
Bronze-type TiO2(B) single-crystal fibers with several microns in length and 300～400 nm in diameter, were synthesized from anatase TiO2 by the supercritical fluid hydrothermal treatment at c.a. 375～425 ˚C under 23～37 MPa in 10 mol • L−1 NaOH aq. followed by ion-exchange of Na to H in dilute HCl aq. and post-heating at 400 ˚C for 5 h in air. Thus prepared TiO2(B) fibers were characterized by XRD analysis, SEM/TEM observations, ED analysis, DTA/TG and BET surface area measurements. Electrical conductivity of the fibers was also evaluated using “Nano-probe” measurement system. Compared to the conventional TiO2(B) fibers prepared from the normal hydrothermal treatment at c.a.185 ˚C for 8 h, the present TiO2(B) showed higher thermal stability; TiO2(B) phase was stable even after heating at 800 ˚C for 1 h in air. And they show an extreme high electrical conductivities of 1.2 ～1.3 S • m−1; they were higher 1011 and 1.5 times than those of anatase TiO2 and conventional TiO2(B), respectively
