Abstract: | Hollow dipyramid titanium dioxide with truncated structure was synthesized by a facile hydrothermal approach in an aqueous solution of hydrofluoric acid and hydrogen peroxide. The critical oxygen from the decomposition of hydrogen peroxide has been investigated in detail. X‐ray diffraction and Raman measurements show that the main phase is anatase titanium dioxide, accompanied by a small amount of rutile titanium dioxide. The formation mechanism is proposed based on oxygen release, oxidation, etching and hydrolyzation. The sensing properties of such a hollow dipyramid titanium dioxide sensor show that the desirable sensing characteristics with a sensitivity of about 2.1 towards 5 ppm ethanol gas at 200 °C could be obtained. |