Unraveling the highly sensitive-selective NO2 sensing characteristics of perfect and agglomerated Zn2SnO4 octahedrons

• Published in: Journal of environmental chemical engineering Vol. 11; no. 5; p. 110648
• Main Authors: Kim, Deasung, Tran, Thanh Thao, Bhatt, Vishwa, Nguyen, Ha Trang, Kim, Joondong, Kumar, Manjeet, Yun, Ju-Hyung
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2023
• Subjects: Hydrothermal method; NO2 gas sensor; Zn2SnO4 octahedron; Zn2SnO4 octahedron; NO2 gas sensor; Hydrothermal method
• ISSN: 2213-3437; 2213-3437
• DOI: 10.1016/j.jece.2023.110648

The increasing fears over the worsening condition of the environment due to pollution caused by urbanization and modernization have turned our attention toward the field of gas sensors. Highly selective, stable, and sensitive gas sensors are getting huge attention due to their applicability to monitoring environmental conditions continuously as well as protecting humans, and other lives from the hazardous effect of air pollutants on this planet. In this work, we synthesized Zn2SnO4 octahedrons by a simple hydrothermal method with various reaction times (6 h, 12 h, and 18 h). The gas sensors based on three kinds of Zn2SnO4 samples are fabricated and the effect of synthesis conditions (reaction time) on their sensing performance is studied. In the results, the Zn2SnO4 sample synthesized in 12 h exhibits the most perfect and smoothed octahedral shape with a size of around 500 nm. Additionally, it shows the highest sensor response value of ∼150 at 250ºC with a gas pumping concentration of 40 ppm, followed by the third and first samples with the value of ∼124 and ∼24, respectively. Such improved NO2 gas sensing characteristics may be ascribed to the octahedral morphology of the synthesized Zn2SnO4 as well as the increased contact area between Zn2SnO4 and target chemical input which might be a promising candidate for selectively detecting the traces of NO2 gas. [Display omitted] •Role of agglomerated & perfect Zn2SnO4 octahedrons for NO2 gas sensing was examined.•The operating temperature reduced from 350 °C to 250 °C for perfect Zn2SnO4 octahedrons.•Maximum NO2 sensor response was up to 150.8 for perfect Zn2SnO4 octahedrons.•Accessible octahedron surface planes & edges must be the dominant factor for NO2 sensing.