Electrospun ZnO–SnO2 heterojunction belts for hydrogen sensing

Abstract

Chemiresistive sensors are promising devices for H 2 sensing in a broad range of applications including fuel cells, hydrogen storage systems, petroleum re nement, and diagnosis of oil-insulated transformers.Herein, electrospun ZnO-SnO 2 belts were synthesized and applied as resistive-type sensing layers for H 2 sensing. The ZnO-SnO 2 belts containing 20 mol% of Zn relative to Sn showed a response (R a /R g ) of 6.7, fast response speed (3.6 sec), and a distinguishable selectivity toward 5 ppm H 2 at 400°C in the presence of HCHO, CH 4 , NH 3 , CO, and CO 2 . The sensor displayed a repeatable response when subjected to 15 cycles of alternate air and 5 ppm H 2 exposure. A unique H 2 sensing performance of the belts was attributed to their belt morphology, numerous surface pores, smaller crystal size, ZnO/SnO 2 heterojunction, and ZnO metallization following H 2 exposure.