Abstract
The nanocomplex oxides of Sn-In and Sn-In-Ti were prepared by controlled co-precipitation method as sensing materials of semiconductor gas sensors for detection of CO, CH4 and NO2. Through manipulating the Sn/In cation ratio, metal salt total concentration, precipitation pH value and aging time, the nanocrystalline powders were successfully derived with chemical homogeneity and superior thermal stability, compared with the single component oxides. The particle size and morphology, surface area, and thermal and phase stabilities were characterized using TEM, TG-DTA, BET and XRD. The sensing tests showed that the Sn-In composites exhibit high sensitivity and selectivity for CO and NO2. The introduction of TiO2 enhanced CH4 sensitivity and selectivity, particularly, additives of Pd and Al2O3 as a dopant and surface modification greatly enhanced the sensing properties. The sensitivity depended on the composition of composites, calcination temperature and operating temperature. The optimal values were (25%In2O3-75%SnO2)-20%TiO2 for temary composite, 600 and 300°C, respectively. Temperature-programmed desorption (TPD) studies were employed to explain the gas adsorption behavior displayed by the surface of nanocomposites and X-ray photoelectron spectroscopic (XPS) analysis was used to confirm the electronic interactions existing between oxide components. The sensing mechanism of the nanocomposites was attributed to chemical and electronic synergistic effects.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Eggins B R. Chemical Sensors and Biosensors (in Chinese). Translated by Luo R X, Chen L H, Chen A F. Beijing: Chinese Chemical Industry Press, 2005
Xu C, Tamaki J, Miura N, et al. Grain size effects on gas sensitivity of porous SnO2-based elements. Sensor Actuat B, 1991, 3: 147–150
Wu N, Wang S, Rusakova L. Inhibition of crystallite growth in the sol-gel synthesis of nanocrystalline metal oxide. Science, 1999, 285: 1375–1381
Huang X D, Bai S L, Luo R X, et al. Preparation, characterization and gas sensing properties of ZnO-SnO2 nanocomposites. Chin J Inorg Chem, 2005, 21(8): 1143–1148
Sung J H, Lee Y S, Lim J W, et al. Sensing characteristics of tin dioxidergold sensor prepared by coprecipitation method. Sensor Actuat B, 2002, 60: 149–153
Ma L J, Yan T, Bai S L, et al. The preparation and gas-sensing properties of nanosize r-Fe2O3/SiO2. Chin J Chem Eng, 2004, 12(2): 282
Enoki E, Echigoya T, Suto H. The intermediate compound in the In2O3-SnO2 system. J Mater Sci, 1991, 26: 4110–4115
Carbot A, Vila A, Morante J R. Analysis of the catalytic activity and electrical characteristics of different modified SnO2 layers for gas. Sensor Actuat B, 2001, 84: 12–20
Zhou X, Cao Q, Huang H, et al. Study on sensing mechanism of CuO-SnO2 gas sensors. Mater Sci Eng, 2003, 99(1): 44–47
Wagner C D, Biloen P. X-ray excited auger and photoelectron spectra of partially oxidized magnesium surface abnormal chemical shifts. Surf Sci, 1973, 38: 82–95
Author information
Authors and Affiliations
Corresponding author
Additional information
Supported by the National Natural Science Foundation of China (Grant No. 20577001) and Beijing Natural Science Foundation (Grant Nos. 8072018, 8062011)
Rights and permissions
About this article
Cite this article
Bai, S., Tong, Z., Li, D. et al. Sensing characterization of Sn/In/Ti nanocomplex oxides for CO, CH4 and NO2 . SCI CHINA SER E 50, 18–26 (2007). https://doi.org/10.1007/s11431-007-0012-6
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11431-007-0012-6