Zinc Oxide Coated Tin Oxide Nanofibers for Improved Selective Acetone Sensing

Three-dimensional hierarchical SnO2/ZnO hetero-nanofibers were fabricated by the electrospinning method followed with a low-temperature water bath treatment. These hierarchical hollow SnO2 nanofibers were assembled by the SnO2 nanoparticles through the electrospinning process and then the ZnO nanorods were grown vertically on the surface of SnO2 nanoparticles, forming the 3D nanostructure. The synthesized hollow SnO2/ZnO heterojunctions nanofibers were further employed to be a gas-sensing material for detection of volatile organic compound (VOC) species such as acetone vapor, which is proposed as a gas biomarker for diabetes. It shows that the heterojunction nanofibers-based sensor exhibited excellent sensing properties to acetone vapor. The sensor shows a good selectivity to acetone in the interfering gases of ethanol, ammonia, formaldehyde, toluene, and methanol. The enhanced sensing performance may be due to the fact that n-n 3D heterojunctions, existing at the interface between ZnO nanorods and SnO2 particles in the SnO2/ZnO nanocomposites, could prompt significant changes in potential barrier height when exposed to acetone vapor, and gas-sensing mechanisms were analyzed and explained by Schottky barrier changes in SnO2/ZnO 3D hetero-nanofibers.