Title: Synthesis of ZnO-Ni flower like nanostructure for gas sensing application

Authors: V.S. Siril; K.N. Madhusoodanan

Addresses: Department of Instrumentation, Cochin University of Science and Technology, Cochin 682022, India ' Department of Instrumentation, Cochin University of Science and Technology, Cochin 682022, India

Abstract: Hierarchical Ni-doped ZnO flower like structures are fabricated by novel hydrothermal route without any capping agents or toxic organic solvents. Characterisation techniques of the prepared ZnO nanostructure include SEM-EDAX, FESEM, TEM in addition to the standard methods such as XRD. Crystallographic structure studies confirm that Ni-doping does not alter the hexagonal structure of pure ZnO. Presence of Zn, O, Ni is confirmed from the elemental compositional analysis. Morphological evolution of ZnO nanostructure reveals the formation of flower shaped aggregated nanorods. The morphology of as prepared Ni doped ZnO nanorods is symmetric with length of 1 µm and diameter of about 84 nm. We further investigated the application of Ni-doped ZnO films in NH3 gas sensing. The sensitivity, operating temperature, response time and recovery time of Ni-ZnO nanorod sensors towards ammonia were conducted and made a detailed analysis of their gas sensing performance. Ni doped ZnO flowers can detect NH3 concentration in the range 3.5-140 ppm at an operating temperature 220°C. They exhibit a rapid response (40 s) and recovery (2.5 min) time for test gas concentration of 140 ppm. The Ni-ZnO flowers revealed better ammonia gas sensing characteristics. To understand the performance of Ni-ZnO sensor, the gas sensing mechanism is explained. All the measurements were done using the automated system with LabView software.

Keywords: metal oxide; Ni-doped ZnO; facile method; hydrothermal synthesis; morphology; nanostructures; flower shaped nanorods; gas sensing; NH3; gas sensor; sensor response.

DOI: 10.1504/IJNT.2021.116166

International Journal of Nanotechnology, 2021 Vol.18 No.5/6/7/8, pp.462 - 471

Published online: 12 Jul 2021 *

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