Porosity Controlled 3D SnO2 Spheres via Electrostatic Spray: Selective Acetone Sensors

摘要： Tailoring of semiconducting metal oxides (SMOs) nanostructures with high porosity is of importance for enhanced gas sensing performance. Hierarchically-assembled SMOs possess high surface area but often suffer from low porosity. Here, bimodal pore-loaded hierarchical SnO2 (PH-SnO2) spheres were successfully synthesized via electrostatic spraying method (e-spraying) combined with colloidal templating route using polystyrene beads. The resulting porous PH-SnO2 spheres were used as sensing layers for detection of acetone, which exhibited improve the sensing performance. As a result, the Pt-functionalized PH-SnO2 (Pt-PH-SnO2) spheres showed dramatically improved acetone detection capability with a response (Rair/Rgas) about 20% enhanced response compared with hierarchical SnO2 (H-SnO2) spheres without through a simple dispersion of catalytic nanoparticle (NPs) in the e-spraying solution to pores. In addition, e-spraying is a fascinating technique for uniform catalytic functionalization selectivity. In this work, the unique combination of e-spraying and PS templating route paves of 44.83 at 5 ppm as compared to PH-SnO2 spheres (Rair/Rgas = 6.61) as well as superior the way for robust and facile synthetic method for bimodal pore loaded 3D hierarchical SMOs, and demonstrates the feasibility for application in exhaled breath sensors.