Bio-synthesis of SnO2 and comparison its CO sensing performance with conventional processes.

The present paper reports on a unique eco-friendly bio-synthesis process of tin oxide using water extract of soaked kabuli chickpea seeds as natural binder. The structural, microstructural and CO sensing properties of the newly synthesized tin oxide were compared with those of conventional sol–gel and sonochemical processes. XRD results of the bio-synthesized material revealed the formation of single tetragonal phase of SnO 2 similar to sol–gel and sonochemical processes. The bio approach led to the formation of finer nanoparticales with a higher specific surface area ∼ 60 m2 /gm compared to the others. The average sizes of tin oxide nanoparticles as observed from TEM images were about 35 nm, 15 and 6 nm for the sonochemical, sol-gel and biosynthesis respectively. These tin oxide powders were used to fabricate Taguchi based sensors and their CO sensing performance were evaluated. The biosynthesized tin oxide sensor showed ∼53% sensing performance for 30 ppm CO which was better than sol-gel (∼44%) or sonochemical (∼42%) tin oxides operating at similar condition. The reported results suggest that the biosynthesis is a promising cost effective method to prepare nanocrystalline SnO 2 for sensing application. Image 1 • Pure tin oxide powder of average particle size ∼6 nm was prepared using water extract of kabuli chickpea seeds. • The structural and morphological properties of this were compared with sol-gel and sonochemical processes. • The sensor fabricated from biosynthesized tin oxide revealed the best sensing performance, ∼53% on exposure of 30 ppm CO. • This sensor was stable and able to detect very low concentration (∼3 ppm) of CO with reproducible performance. • The mechanism for the formation of nanoparticles and better sensitivity has been illustrated. [ABSTRACT FROM AUTHOR]