Development of a Zirconia-Based Electrochemical Sensor for the Detection of Hydrogen in Air

摘要

Mixed potential sensors utilizing a machined, dense indium-tin oxide working electrode (In{sub}2O{sub}3:SnO{sub}2; 90%: 10%), a Pt wire counter electrode, and porous YSZ electrolyte were prepared using ceramic tape casting methods. The response of these devices to hydrogen concentrations up to 2% in air were studied from 600 to 740°C. The sensor response exhibited a reversible behavior and a fast response time with sensitivity increasing with decreasing temperature. GC analysis confirmed significant heterogeneous oxidation of the H{sub}2 on heated furnace tube wall surfaces thus driving sensor response at H{sub}2 concentrations greater than a few hundred ppm. The transition to a cold wall, miniature platform heater significantly reduced hydrogen oxidation although some flow rate dependence remains.