A Sensor Array Realized by a Single Flexible TiO2/POMs Film to Contactless Detection of Triacetone Triperoxide

Abstract

The homemade explosive, triacetone triperoxide (TATP), is easy to synthesize, sensitive to detonation but hard to detect directly. Vapor sensor arrays composed of a few sensor materials have the potential to discriminate TATP, but the stability of the sensor array is always a tricky problem since each sensor may encounter a device fault. Thus, a sensor array based on a single optoelectronic TiO2/PW11 sensor was first constructed by regulating the excitation wavelength to discriminate TATP from other explosives. By in situ doping of Na3PW12O40, a Keggin structure of PW11 formed on the TiO2 to promote the photoinduced electron-hole separation, thus obviously improving the detection sensitivity of the sensor film and shortening the response time. The response of the TiO2/PW11 sensor film to TATP under 365, 450 and 550 nm illumination is 81%, 42%, and 37%, respectively. The TiO2/PW11 sensor features selectivity to TATP and is able to detect less than 50 ppb. The flexibility and stability of the flexible sensor film is also demonstrated with the extent of bending. Furthermore, the sensing response cannot be affected by ambient air below 60% relative humidity.

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

“…Thus, the photoelectrons accumulate at the interface of the homojunction to provide photocatalysis active site to reduce TATP to acetone and hydrogen peroxide (Figure 11c). [29]. One can see from Figure 10a that the response of TiO 2 -FTO-HJ to TATP vapors is nearly three times as strong as the response of TiO 2 -ITO-HJ to TATP.…”

“…It can be seen from Figure 9b that the band gap of TiO2-FTO is 3.02 eV, and the band gap of TiO2-ITO, FTO-HJ, ITO-HJ is 3.04 eV, respectively, suggesting that these TiO2 nanostructures may be promising for sensing [28]. The gas sensing performance diagram of TiO2-FTO-HJ, TiO2-ITO-HJ, TiO2-FTO and TiO2-ITO to TATP vapors was evaluated under simulated natural light [29]. One can see from Figure 10a that the response of TiO2-FTO-HJ to TATP vapors is nearly three times as strong as the response of TiO2 -ITO-HJ to TATP.…”

“…This can be attributed to the homojunctions formation between the urchin-shaped TiO 2 and TiO 2 nanoarrays, which may be beneficial in promoting the efficient separation of photogenerated charges. The gas sensing performance diagram of TiO2-FTO-HJ, TiO2-ITO-HJ, TiO2-FTO and TiO2-ITO to TATP vapors was evaluated under simulated natural light [29]. One can see from Figure 10a that the response of TiO2-FTO-HJ to TATP vapors is nearly three times as strong as the response of TiO2 -ITO-HJ to TATP.…”

Surface Persistence of Trace Level Deposits of Highly Energetic Materials

“…The residence time of a highly energetic material (HEM) on a surface can be defined as the time that the material persists on the surface after its deposition. The concept is essential for the development of samples and standards for trace detection systems [1][2][3][4][5][6][7][8][9][10][11][12]. Aside from adhesion considerations, the residence time mainly depends on the vapor pressure of the compound and surface-HEM interactions.…”

Fingerprinting of Nitroaromatic Explosives Realized by Aphen-functionalized Titanium Dioxide

“…However, the stability of the sensor array [11,12] is dependent on the synergistic effects of the different sensor units, and failure of a single unit can affect the performance of the sensor array. To this end, our previous work constructed a sensor array using a single sensor unit by illumination of different excitation wavelengths [13].…”