Using organo-tin Sn(OC4H9)4 as precursor, sodium dodecyl sulfonate (SDS) and SDS-gelatin (SDS-G) complex as template, two tin dioxide colloidal particles were prepared by a self-assembly method. Both SnO2 products were respectively labelled SnO2-B particles with SDS and SnO2-C particles with SDS-G, which are applied in fabricating SnO2 gas sensors corresponding to SnO2-B' and SnO2-C' sensors. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermo-gravimetry and different thermal analysis (TG/DTA) were used for characterizations. The experimental results show that SnO2-B colloidal particles are composed of mesoporous piece-like particles, while SnO2-C particles mainly consist of spherical particles. Gas sensing measurements show that SnO2-B' sensor performs the best sensing response to all target gases, including H2, C2H5OH and liquid petroleum gas (LPG). In particular, the sensing response of SnO2-B' sensor is achieved at 32 in H2 atmosphere at the concentration of 1000×10-6 M. The gas sensing mechanism was purposely discussed from the electron transfer process and the microstructures of the as-prepared SnO2 products. It is found that serious agglomerations in SnO2-B' particles facilitate the high gas sensing performance of SnO2-B' sensor, while mesoporous structures in SnO2-C' particles decrease the gas sensing response of SnO2-C' sensor.
