Low concentration ammonia sensing performance of Pd incorporated indium tin oxide.

Abstract Indium tin oxide powders containing different amount of tin were prepared using a facile water based sol-gel procedure. The structural and microstructural properties have been analysed with X-ray diffractometer, FTIR-spectroscopy, XPS, TEM and EDX analysis. The nanocrystalline powders were used to fabricate Taguchi design based thick film sensors and their low concentration ammonia sensing (30 ppm) performance were evaluated in the operating temperature range of 200–400 °C. Indium tin oxide sensor having 20 wt% tin oxide showed the optimum response, ∼61% for 30 ppm ammonia at operating temperature of 300 °C. Pd incorporation led to a significant enhancement in sensing response (∼82%) at the same condition. A good sensing response (∼43%) was also observed even at very low ∼ 3 ppm of ammonia concentration. The interference of other gases was almost insignificant. The sensor was stable as reflected from the observation of negligible decrease in the sensing performance of sample up to 90 days period. The sensing mechanism for enhancement has also been explained. Graphical abstract Image 1 Highlights • Different compositions of indium tin oxide were prepared using a unique procedure. • I 80 T 20 O sensor reveals optimum sensing response, ∼61% towards 30 ppm NH 3 at 300 °C. • 1 wt% Pd incorporation enhanced the sensitivity by ∼20%. • The sensor can detect very low concentration of NH 3 with reproducible performance. • It is also very stable and selective. [ABSTRACT FROM AUTHOR]