LaCoO3 Perovskites for CO Sensing

LaCoO3-ss (1:1, 1:5 (high Co), and 5:1 (high La)) perovskites were prepared by the solid state reaction method and their properties were characterized by using X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray absorption near-edge structure (XANES), and specific surface area measurements. Their properties were compared with those of the samples prepared by co-precipitation (LaCoO3-cp) and the modified wet powder dispersion (LaCoO3-wd) methods. To study the CO sensing response, the resistance of LaCoO3-ss (1:1, high Co, and high La), LaCoO3-cp, and LaCoO3-wd perovskites were measured. The LaCoO3-ss (1:1) showed the lowest resistance compared to the others. The fabricated sensors had been tested as CO gas sensors with a CO concentration of 0.006-0.039% v/v at 7.5 volts. The LaCoO3-ss (1:1) sensor had the highest CO sensing capability as compared to the others. The detection limits of LaCoO3-ss (1:1) on sensing CO was 0.006% (60 ppm) for the CO concentration with a sensitivity of 1.007.