High selectivity to ppb-level HCHO sensor based on mesoporous tubular SnO2 at low temperature

Distinctive mesoporous SnO 2 microtubes were synthesized via a facile and environmentally friendly solvothermal method. The gas sensor based on such SnO 2 microtubes exhibited not only the lower detection limit to detect formaldehyde and remarkable selectivity comparison with other various gases when operating within 92   °C, but also good linear relationship under concentration ranges of ppm level (1–100   ppm) and ppb level (10–100   ppb). The sensing properties of such SnO 2 microtubes have been greatly improved compared to previously reported hollow structures. This might be attributed to their large specific surface area and porous structure, which can promote the diffusion of gas molecules and their adsorption on the surface of the sensing material.