Efficient H-2 Gas Sensor Based On 2d Sno2 Disks: Experimental And Theoretical Studies

2D SnO2 disks with excellent purity and crystallinity were synthesized through a low cost, facile hydrothermal process and were characterized in terms of their morphological, structural, optical and electrochemical properties. The 2D disk-like morphology of synthesized SnO2 presented the average thickness of similar to 1 mu m and possessed the typical rutile tetragonal phase for the SnO2 with preferred growth along (100) plane. As-synthesized SnO2 disks were used for the fabrication of gas sensors for reducing gases like H2, CO, and C3H8. With the optimized temperature at 400 degrees C, the as-synthesized SnO2 electrode expressed the gas responses of 14.7, 9.3 and 8.1 for H-2, CO, and C3H8, respectively. Contrary, the reasonable response times of 4 s, 3 s, and 8 s and the recovery times of 331 s, 201 s, and 252 s were recorded for H-2, CO, and C3H8 gases, respectively. The DFT studies conducted herein suggest that the adsorbed oxygenated species act as a primary redox mediator for gas sensing reaction between reductive gases like H-2, CO and C3H8 , and SnO2 sensor. From DFT analysis, a very low heat of adsorption (<= 0.2 eV) estimated which suggested the physisorption of the H-2 molecules on the surface of the sensing material (i.e. SnO2). In contrast, the deposited oxygen atom forms strong chemical bonds with O-2c and O-3c sites. The oxygen atom bonded to O-2c site control the conductivity of the sensor better than the O-3c sites. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.