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

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 degrees 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 degrees 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.