Electrospun ZnO-SnO2 Heterojunction Belts for Hydrogen Sensing

Abstract

Abstract Chemiresistive sensors are promising devices for H2 sensing in a broad range of applications including fuel cells, hydrogen storage systems, petroleum refinement, and diagnosis of oil-insulated transformers. Herein, electrospun ZnO-SnO2 belts were synthesized and applied as resistive-type sensing layers for H2 sensing. The ZnO-SnO2 belts containing 20 mol% of Zn relative to Sn showed a response (Ra/Rg) of 6.7, fast response speed (3.6 sec), and a distinguishable selectivity toward 5 ppm H2 at 400°C in the presence of HCHO, CH4, NH3, CO, and CO2. The sensor displayed a repeatable response when subjected to 15 cycles of alternate air and 5 ppm H2 exposure. A unique H2 sensing performance of the belts was attributed to their belt morphology, numerous surface pores, smaller crystal size, ZnO/SnO2 heterojunction, and ZnO metallization following H2 exposure.