Low Temperature Methanol Sensors Based on Cobalt Ferrite Nanoparticles, Nanorods, and Porous Nanoparticles

In this research, response of various nanostructures of cobalt ferrite including nanoparticles, nanorods and porous nanoparticles to methanol is investigated and compared. The nanostructures were prepared using a hydrothermal method and their crystallographic, morphologic and magnetic characteristics were studied by x-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) analysis. Sensing performance of low-cost (PCB-based) sensors to methanol vapor was evaluated at different temperatures. The results showed that the sensors have the best response at low temperatures, as the optimum working temperature of cobalt ferrite nanoparticles and nanorods sensors was 90°C while the optimum performance of porous nanoparticles sensor was at room temperature (RT). The responses of sensors based on cobalt ferrite nanoparticles, porous nanoparticles and nanorods at their optimum working temperatures to 100 ppm methanol were 42.4% (90 °C), 20.26% (RT), and 13.3% (90 °C), respectively. Compared to the previous works, our proposed sensors have high responses to methanol at low temperatures. Furthermore, our sensors are repeatable, have a good stability, and can easily be recovered in air at their working temperatures.