Synthesis and characterization of Sm2O3 nanorods for application as a novel CO gas sensor

Sm2O3 nanorods have been successfully synthesized by a simple hydrothermal process in the presence of cetyl trimethyl ammonium bromide (CTAB) as an organic template. The morphological, microstructural and optical characteristics of the synthesized nanorods were investigated by scanning electron microscopy (SEM-EDX), X-ray diffraction analysis (XRD), micro-Raman spectroscopy and photoluminescence (PL). The complementary investigations substantiated the purity of the material synthesized, constituted of Sm2O3 nanorods in the single cubic crystalline phase having a mean length of about 400 nm and diameter of about 80 nm. A conductometric sensor based on the synthesized Sm2O3 nanorods has been developed. The sensor performances were investigated in the detection of carbon monoxide (CO) in air. At the optimal operating temperature of 250 degrees C, the sensor showed a response S = R-g/R-a = 1.4 toward 5 ppm of CO, a limit of detection (LOD) of 1 ppm at signal-to-noise ratio S/N = 3, fast response/recovery time (35 s and 110 s, respectively) and selectivity against the most common air pollutant gases. The results demonstrated that the developed sensor based on Sm2O3 nanorods has superior performances in the monitoring of low concentration of CO in air compared to the state of the art rare-earth oxide CO sensors.