Low-temperature/room-temperature gas sensing application for NO2 gas by SnO2 and Ni doped SnO2 nanostructures synthesized by sol-gel method

Abstract

Gas sensors are the attentive parts for the day-to-day applications in advanced manufacturing, chemical industries and advanced applications need the better performing materials. SnO2 (wide band gap-3.27eV, n-type semiconductor) and Ni-doped SnO2 are the suitable materials for gas sensing in the fields of forward-looking technology. Pure and Ni-doped SnO2 particles were synthesized by sol-gel method and started with 0.2 mol of SnCl2, added with 2 ml of acetic acid, and pH controlled by the addition of 8 mol NaOH, till pH reaches desired value and Ni is doped. Finally washed, dried, and calcined at 400° C. The prepared pure and Ni(0.02 and 0.04 mol)-doped SnO2 nanostructures were characterized by XRD, EDAX, DSC, and SEM techniques. Average crystallite size is calculated by XRD and varied from 8 to 5 nm. Morphology shows difference, while the Ni concentrations changed. Particle size is estimated by transmission electron microscope (TEM), found to be 8–12 nm and well correlated with XRD analysis. The Energy gap is calculated with the UV–Vis spectrometer, and values are 3.21, 3.60, and 3.56 eV. Finally, the application part was carried out for NO2 gas sensing at a low level of 7–19 parts per million (PPM) at 40 °C, response and recovery times are 6 and 9 min respectively for all PPMs. Sensitivity of the samples of pure and Ni doped samples have 99 to 99.9 and 80 %. Pure and 0.02 mol Ni doped samples have the good achievement for sensitivity and 0.04 mol Ni doping has increase in conductance.

Keywords

• SnO2nanoparticles
• Sol-gel
• SEM
• TEM
• Gas sensors