Construction of Rutile-TiO2 Nanoarray Homojuction for Non-Contact Sensing of TATP under Natural Light

Triacetone triperoxide (TATP) is a new terrorist explosive, and most nitrogen-based sensors fail to detect TATP. Herein, a sea urchin-like TiO2-covered TiO2 nanoarray is constructed as a TATP-sensitive homojunction (HJ) by one step hydrothermal method. By taking fluorine-doped tin oxide (FTO) and indium tin oxide (ITO) conducting glass as the substrate, the conducting glass is horizontally and vertically put in the reactor to epitaxially grow TiO2-FTO, TiO2-ITO, TiO2-FTO-HJ and TiO2-ITO-HJ. TiO2-FTO-HJ shows a broad absorption band edge in the visible region and high sensitivity to TATP under the simulating natural light compared with TiO2-FTO, TiO2-ITO, and TiO2-ITO-HJ. E-field intensity distribution simulation reveals that constructing homojunctions between the urchin-shaped TiO2 nanosphere and TiO2 nanoarrays can enhance the localized electromagnetic field intensity at the interface of junctions, which may provide photocatalysis active sites to reduce TATP molecules by promoting charge separation. Moreover, the TiO2-FTO-HJ shows high selectivity to TATP among ammonium nitrate, urea and sulfur, which are common homemade explosive raw materials.