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 SnO2 similar to sol-gel and sonochemical processes. The bio approach led to the formation of finer nanoparticales with a higher specific surface area similar to 60 m(2)/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 similar to 53% sensing performance for 30 ppm CO which was better than sol-gel (similar to 44%) or sonochemical (similar to 42%) tin oxides operating at similar condition. The reported results suggest that the biosynthesis is a promising cost effective method to prepare nanocrystalline SnO2 for sensing application. (C) 2019 Elsevier B.V. All rights reserved.