Heating-sol–gel template process for the growth of TiO2 nanorods with rutile and anatase structure

Densely assembled nanorods consist of the nanoparticles of rutile and those of anatase have been fabricated successfully by a heating-sol–gel template process, respectively. The size of nanorods varies as a diameter of 100–300 nm and a length of several micrometers, which are controllable by the pore size of the template. The similarities and/or differences of the fabricated process and microstructure for rutile and anatase nanorods were discussed. TEM image revealed that anatase nanorods are the aggregates of many indistinct polygonal nanoparticles up to 10 nm in diameter, while rutile nanorods are the aggregates of irregular octagon and/or hexagon nanoparticles in 10–30 nm diameter. XRD, ED and HRTEM lattice image confirmed the nanorods fabricated by the heating-sol–gel process are well assembled by many individual nanoparticles. The nanoparticles in rutile nanorods were larger than those in anatase nanorods possibly due to the different heat-treatment procedure