Preparation of large mesoporous SnO2 powder for gas sensor application

Large mesoporous SnO2 powders have been prepared by employing SnCl2·H2O as an Sn-source and the self-assembly of a triblock copolymer as a surfactant. Large mesoporous structure along with a sharp pore size distribution around 4 nm and a crystallite size of 4 nm could be maintained in the resultant powders even after calcination at 600 °C for 5 h by phosphoric acid (PA) treatment of the as-precipitated product. Pore volume and specific surface area of the resulting powders varied with the surfactant concentrations in the precursor solutions. The largest specific surface area, as large as 253 m2 g−1, was achieved at the surfactant concentration of 1.3 wt.%. Thick film sensors prepared from the PA-treated large mesoporous SnO2 powders showed large H2 response, in comparison with the sensors prepared from untreated large mesoporous powder and from PA-treated mesoporous powder reported previously. However, no clear correlation was observed between the H2 response and the morphological characteristics of the sensors.