Mesoporous Ultrathin SnO₂ Nanosheets in Situ Modified by Graphene Oxide for Extraordinary Formaldehyde Detection at Low Temperatures

In this article, we demonstrated an extremely high-sensitivity formaldehyde (HCHO) gas sensor, where the graphene oxide (GO) in situ modified two-dimensional (2D) SnO2 nanosheets with in-plane mesopores were utilized as the sensing materials. The sensor response (Ra/Rg) was larger than 2000 toward 100 ppm HCHO at 60 °C. In addition, the selectivity for detecting HCHO was excellent against other interferences including ethanol, acetone, methanol, toluene, ammonia, water, etc. The outstanding sensing performance of 2D mesoporous GO/SnO2 nanosheets was attributed to the synergism of the sensitizer effect of GO, large surface areas of 2D nanostructure, suitable particle size, and abundant in-plane mesopores. The high sensitivity, high selectivity, and low working temperature of the sensor reported here endowed it a great potential in selective detection of HCHO. Meanwhile, the design and synthesis of GO/SnO2 nanocomposites will provide new paradigms in the future development of HCHO-sensitive materials