Prominent Gas Sensing Performance of TiO₂-Core/NiO-Shell Nanorod Sensors

다국어 초록 (Multilingual Abstract)

<P>TiO2 nanorods and TiO2-core/NiO-shell nanorods were synthesized using facile hydrothermal techniques and their acetone sensing properties were examined. X-ray diffraction and scanning electron microscopy revealed the good crystallinity and uniformity of the TiO2-core/NiO-shell nanorods in terms of its shape and size. The TiO2-core/NiO-shell nanorod sensor showed a stronger response to acetone than the pristine TiO2 nanorod sensor. The response of the core-shell nanorod sensor to 200 ppm of acetone at 400 degrees C was 9.81, whereas that of the pristine nanorod sensor was 5.76 under the same conditions. Furthermore, under these conditions, the recovery time of the core-shell nanorod sensor was 136 s, which was much shorter than that of the pristine nanorod sensor (498 s), even though the response time of the former (14.6 s) was slightly longer than that of the latter (5.2 s). The core-shell nanorod sensor showed excellent selectivity to acetone over other volatile organic compound gases including ethanol, methanol, benzene, and toluene. The improved sensing performance of the core-shell nanorod sensor is attributed to modulation of the conduction channel width at the TiO2-NiO interface accompanying the adsorption and desorption of acetone gas as well as preferential adsorption and diffusion for oxygen and acetone molecules at the TiO2-NiO interface.</P>