A facile approach to fabricate three-dimensional ordered macroporous rutile titania at low calcination temperature

Although ordered macroporous rutile titania is seldom successfully fabricated because it is hard to maintain its integrated structure at the high calcination temperature, we herein describe a facile approach to obtain inverse rutile titania opals under a relatively mild condition. By employing SnO2 as the additive for enhancing the phase transformation from anatase to rutile, we investigated various kinds of differences (pore size, backbone filling fraction, reflection peaks, etc.) between the macroporous structures with the two different kinds of crystalline phases (anatase and rutile), which were hardly stressed in other reports because the two phases could not be obtained separately under the same calcination condition if using other approaches.