Highly Efficient Electronic Sensitization of Non-oxidized Graphene Flakes on Controlled Pore-loaded WO3 Nanofibers for Selective Detection of H2S Molecules

Abstract

Tailoring of semiconducting metal oxide nanostructures, which possess controlled pore size and concentration, is of great value to accurately detect various volatile organic compounds in exhaled breath, which act as potential biomarkers for many health conditions. In this work, we have developed a very simple and robust route for controlling both the size and distribution of spherical pores in electrospun WO3 nanofibers (NFs) via a sacrificial templating route using polystyrene colloids with different diameters (200 nm and 500 nm). A tentacle-like structure with randomly distributed pores on the surface of electrospun WO3 NFs were achieved, which exhibited improved surface area as well as porosity. Porous WO3 NFs with enhanced surface area exhibited high gas response (Rair/Rgas = 43.1 at 5 ppm) towards small and light H2S molecules. In contrast, porous WO3 NFs with maximized pore diameter showed a high response (Rair/Rgas = 2.8 at 5 ppm) towards large and heavy acetone molecules. Further enhanced sensing performance (Rair/Rgas = 65.6 at 5 ppm H2S) was achieved by functionalizing porous WO3 NFs with 0.1 wt% non-oxidized graphene (NOGR) flakes by forming a Schottky barrier (ΔΦ = 0.11) at the junction between the WO3 NFs (Φ = 4.56 eV) and NOGR flakes (Φ = 4.67 eV), which showed high potential for the diagnosis of halitosis.

Porous reduced graphene oxide (rGO)/WO3 nanocomposites for the enhanced detection of NH3 at room temperature

“…As previously reported, the rGO/WO 3 nanocomposite is a promising candidate for detecting many toxic gases such as NO 2 , H 2 S, acetone and so on. [43][44][45][46] In the present work, sensing of NH 3 , as the target vapour is demonstrated using rGO/WO 3 nanocomposites. So far, there are no specic reports on the use of rGO/WO 3 nanocomposites towards NH 3 sensing at room temperature.…”

The manufacture and characteristics analysis of electrospun tungsten trioxide nanofibers

“…It was also shown that PVP is evaporated at more than 515 °C. [17] The fibers shown in Figure 4 were calcined at 500 °C for one and 2 h. It can be seen that the fiber surface is granular and rough. Image J software was used to measure the diameter of six randomly selected fibers on each image.…”

“…The second step weight loss of 37% was the result of temperature decomposition of the organic compounds and PVP at 250-300 °C and 300-515 °C, respectively. [17] The SEM images (Hitachi SU8000) in Figure 3 show the shape of fibers that have been calcined for 1 h at temperatures from 400 to 550 °C. As the temperature is increased, the fiber structure begins to show damage.…”

Realization of ppb-Scale Toluene-Sensing Abilities with Pt-Functionalized SnO2–ZnO Core–Shell Nanowires

“…The information needed to diagnose a specific disease can be obtained from the detection of specific VOCs, which are known as biomarkers and have strong correlations with specific diseases. 25-29 A number of biomarkers in exhaled breath have been identified in previous studies [30][31][32][33][34][35][36][37][38][39][40] ; hydrogen sulfide, 30,31 acetone, 32,33 toluene, 34,35 ammonia, [36][37][38] and carbon monoxide 39,40 are recognized biomarkers for halitosis, diabetes, lung cancer, kidney failure, and asthma, respectively. However, the actual implementation of chemiresistive SMO NW sensors to diagnose specific diseases is still challenging because of their insufficient sensitivity to detect the extremely small variations of disease markers that exist in exhaled breath.…”