LAUSR

In this paper, different MnO2 nanostructures were grown employing hydrothermal route by varying the deposition time and corresponding alcohol vapor sensing performance were duly performed. Four types of hierarchical MnO2 nanostructures, viz. three-dimensional (3-D) nanoflowers (comprising of 2-D nanosheets), 3-D nanoflowers (comprising of a combination of 1-D nanorods and 2-D nanosheets), 3-D nanourchin (comprising of 1-D nanorods), and 3-D nanourchin (comprising of 1-D nanotubes) were grown for the deposition time of 3h, 6h, 9h, and 12h, respectively. The nanoforms were characterized using field emission scanning electron microscopy and transmission electron microscopy. These nanostructures were employed as the sensing layer for detecting alcohol vapors, as the test species, in the concentration range of 10–400 ppm. The best sensing performance was offered by the fourth one, due to the synergistic hybridization of 1-D nanotubes which are distributed over 3-D space, facilitating the target species adsorption and diffusion in all possible directions and enabling the interaction of the same with both the inner and the outer wall of the tubes. On the contrary, the mixed nanoheterostructure offered the best response magnitude with relatively poor transient kinetics than that of nanotubes based nanourchin structure.