Nitrogen-doped ZnO microspheres with a yolk-shell structure for high sensing response of triethylamine
Yangyang Sun, Huiqing Fan, Shuwen Zhu, Hui Wang, Wenqiang Dong, Mohammed Al‐Bahrani, Weijia Wang, Longtao Ma
Abstract
Triethylamine is a kind of volatile organic compounds , which is harmful and toxic to the environment and people. Therefore, triethylamine gas sensors are increasingly demanded in practical applications. In this work, we synthesized the nitrogen-doped ZnO yolk-shell microspheres with mesoporous distribution by a facile strategy of hydrothermal-annealing. The influence of the amount of hexamethylene tetramine on the morphology of yolk-shell ZnO was studied and the yolk-shell ZnO (YSZ-3) prepared with 0.3 g hexamethylene tetramine showed the best gas sensing performances for triethylamine at 370 ℃. The response to 100 ppm triethylamine was 133. Moreover, a low triethylamine detection limit was achieved (1 ppm), with a response value of 2.6. The prepared yolk-shell ZnO showed an excellent selectivity to triethylamine, over ethanol, methanol, acetone, formaldehyde, ammonia, and toluene. Furthermore, YSZ-3 offered a low theoretical detection limit (42.4 ppb) and a fast response and recovery (20 s/5 s). Finally, the growth mechanism and gas sensing mechanism of yolk-shell ZnO were discussed.