Pd-functionalized core-shell composite nanowires for self-heating, sensitive, and benzene-selective gas sensors

Abstract

We devised a new low power consumption nanocomposite sensor based on Pd-functionalized SnO2-ZnO core-shell nanowires (C-S NWs) in self-heating mode. Functionalization of Pd nanoparticles (NPs) was performed by γ-ray radiolysis at room temperature. Characterization results confirmed formation of the C-S NW morphology with the desired composition. The effects of various applied voltages (1−20 V) and different gases upon the sensing response of synthesized NWs was examined. In particular, increasing the applied voltage increased the gas sensitivity, where the response for 50 ppm C6H6 was 1.19 at 3 V, and it increased to 2.62 at 20 V through the generation of heat within the sensor via self-heating. Additionally, the sensors revealed outstanding selectivity towards C6H6. The effects of sensing temperatures (RT-200 °C) without applied voltages were also studied. The high response to C6H6 along with the excellent selectivity was due to the unique design of the sensor and the catalytic activity of Pd towards C6H6. The sensor in self-heating mode consumed only 70.5 nW at 5 V, indicating a good potential to be integrated in portable, low power consumption electronic devices.