Ultrasensitive nitric oxide gas sensor based on gold/tin oxide composite nanofibers prepared by electrospinning

Superior gas sensing properties may be obtained by forming suitable metal/semiconductor nanocomposites. In this work, gold (Au) was utilized to form composite nanofibers with tin oxide (SnO 2 ) to detect nitric oxide (NO) gas. Au/SnO 2 composite nanofibers were synthesized through a facile electrospinning and annealing treatment. Various techniques, including XRD, SEM, TEM, UV–vis, XPS, and BET, were used to characterize these Au/SnO 2 heterostructures. The characterization results demonstrate that Au exists in the form of metallic clusters even at an extremely low concentration of 0.1 at% and, it can provide more active sites and chemisorbed oxygen species due to its spillover effect. The gas sensing results show that the Au/SnO 2 composite nanofibers exhibit excellent sensing performance to NO at 130 °C. Specifically, the composite nanofiber with 0.1 at% Au shows an ultrahigh response of 183 (resistance ratio) to 100 ppb NO gas at 130 °C. The sensor exhibits good selectivity, repeatability, and long-term stability. These remarkable sensing properties indicate that Au/SnO 2 composite nanofibers have promising applications to some demanding fields such as detecting NO from human exhaled breath.