Department of Chemistry and Center for NanoScience (CeNS), University of Munich (LMU), Butenandtstrasse 5-13, 81377 Munich, Germany.
ACS Nano. 2010 Sep 28;4(9):5373-81. doi: 10.1021/nn100785j.
Crystalline niobium-doped titania nanoparticles were synthesized via solvothermal procedures using tert-butyl alcohol as a novel reaction medium, and their assembly into mesoporous films was investigated. The solvothermal procedure enables the preparation of crystalline doped and undoped nonagglomerated titania nanoparticles, whose size can be controlled from 4 to 15 nm by changing the reaction temperature and time. The anatase lattice of these particles can incorporate more than 20 mol % of Nb ions. The nanoparticles can be easily dispersed at high concentrations in THF to form stable colloidal suspensions and can be assembled into uniform porous mesostructures directed by the commercial Pluronic block copolymer F127. The resulting mesoporous films show a regular mesostructure with a d spacing of about 17 nm, a uniform pore size of about 10 nm with crystalline walls, a high porosity of 43%, and a large surface area of 190 m(2) cm(-3). Substitutional doping with niobium ions drastically increases the electrical conductivity of the titania particles. The electrical conductivity of as-prepared nanoparticles containing 20 mol % of Nb is 2 x 10(-5) S cm(-1); it increases to 0.25 S cm(-1) after treatment at 600 °C in nitrogen.
采用正丁醇作为一种新型的反应介质，通过溶剂热法合成了掺铌的锐钛矿纳米晶，并研究了其组装成介孔薄膜的情况。溶剂热法能够制备出晶态掺杂和未掺杂的无团聚的锐钛矿纳米颗粒，通过改变反应温度和时间，可以将其粒径从 4nm 至 15nm 进行控制。这些颗粒的锐钛矿晶格可以掺入超过 20mol%的 Nb 离子。纳米颗粒可以在高浓度的四氢呋喃中很容易地分散，形成稳定的胶体悬浮液，并可以通过商业的 Pluronic 嵌段共聚物 F127 组装成均匀的多孔介观结构。所得的介孔薄膜显示出规则的介观结构，具有约 17nm 的 d 间距、约 10nm 的均匀孔径和结晶壁、43%的高孔隙率以及 190m(2)cm(-3)的大比表面积。Nb 离子的替代掺杂极大地提高了 TiO2 颗粒的电导率。含 20mol%Nb 的制备好的纳米颗粒的电导率为 2×10(-5)Scm(-1)；在氮气中 600°C 处理后，其电导率增加到 0.25Scm(-1)。
