Low concentration acetone gas sensing properties of 3 wt% Pd-doped SmCoxFe1-xO3 nanocrystalline powders under UV light illumination

3 wt% Pd-doped SmCoxFe1-xO3 nanocrystalline powders were prepared by the sol-gel method and annealed at 750 degrees C. The sensing response of Pd: SmCo0.1Fe0.9O3 was measured to be 1.62, 1.85, 2.21, 2.59, 3.69, 8.48, and 13.86 for 0.01, 0.02, 0.05, 0.1, 0.2, 0.5 and 1 ppm acetone gas, respectively, at an optimal operating temperature of 220 degrees C. The response and recovery times following exposure to 0.5 ppm acetone gas were 32 s and 13 s, respectively. To decrease the optimal operating temperature, UV light illumination at a wavelength of 365 nm was introduced. Under the UV light, the response showed a large improvement to 1.98, 2.53, 3.68, 5.03, 7.68, 10.31, and 15.85 for the same acetone gas concentrations, respectively, at an optimal operating temperature of 160 degrees C. Pd:SmCoxFe1-xO3 can be used to distinguish between healthy individuals and possible diabetic patients. Exhaled breath from four volunteers was detected under UV-light illumination. The resulting data show that the exhaled breath from diabetics contained more than 1 ppm acetone gas, while approximately 0.2 ppm acetone gas was detected in the exhaled breath from healthy individuals. (C) 2017 Published by Elsevier B.V.