Highly sensitive and fast responding CO sensor using SnO2 nanosheets

A highly sensitive and fast responding CO sensor was fabricated from a sheet-like SnO2. The SnO sheets were prepared by a room temperature reaction between SnCl2, hydrazine and NaOH, and they were subsequently oxidized into SnO2 sheets at high temperature (600 °C). The morphology and size of the SnO2 sheets could be controlled during the formation of SnO, which influence the sensor response (Ra/Rg) and response time to a great extent. The sensor response of SnO nanosheets to 10 ppm CO was enhanced up to 2.34, and the 90% sensor response time could be reduced to 6 s, which are significantly higher and shorter than those of SnO2 powders (1.57 and 88 s), respectively. The realization of both a high sensitivity and rapid response were explained in terms of rapid gas diffusion onto the entire sensing surface due to the less-agglomerated and very thin structure of SnO2 nanosheets and the catalytic effect of Pt.