Microwave processing for the low cost, mass production of undoped and in situ catalytic doped nanosized SnO2 gas sensor powders

Nanosized tin oxide powders were obtained for application in thick film gas sensor technology. This requires an innovative technique, involving the use of microwave energy with a wavelength of 2.45 GHz, which produces doped or undoped powder precursors in just a few minutes. Further stabilisation treatments — conventional heating, OH-stimulated microwaves and combined treatments — were also considered. Reproducibility, low cost and suitability for mass production demonstrate the industrial and scientific feasibility of this new procedure. Material structural characterisation and electrical properties after gas exposure of improved sensors of Pt and Pd in situ doped, and undoped SnO2 are introduced, showing the suitability of the material.