Prominent ethanol sensing with Cr2O3 nanoparticle-decorated ZnS nanorods sensors

Abstract

ZnS nanorods and Cr2O3 nanoparticle decorated ZnS nanorods were synthesized\nusing facile hydrothermal techniques and their ethanol sensing properties were\nexamined. X-ray diffraction and scanning electron microscopy revealed the good\ncrystallinity and size uniformity of the ZnS nanorods. The Cr2O3 nanoparticle\ndecorated ZnS nanorod sensor showed stronger response to ethanol than the\npristine ZnS nanorod sensor. The responses of the pristine and decorated\nnanorod sensors to 200 ppm of ethanol at 300oC were 2.9 and 13.8, respectively.\nFurthermore, under these conditions, the decorated nanorod sensor showed longer\nresponse time (23 s) and shorter recovery time (20 s) than those of the\npristine one (19 and 35 s, respectively). Consequently, the total sensing time\nof the decorated nanorod sensor (42 s) was shorter than that of the pristine\none (55 s). The decorated nanorod sensor showed excellent selectivity to\nethanol over other volatile organic compound gases including acetone, methanol,\nbenzene, toluene, whereas the pristine one failed to show selectivity to\nethanol over acetone. The improved sensing performance of the decorated nanorod\nsensor is attributed to the modulation of the conduction channel width and the\npotential barrier height at the ZnS Cr2O3 interface accompanying the adsorption\nand desorption of ethanol gas as well as the greater surface to volume ratio of\nthe decorated nanorods than the pristine one due to the existence of the ZnS\nCr2O3 interface.\n