Selective Hydrogen Detection in a Highly Contaminated Background Using Only a Single Generic Metal Oxide Gas Sensor

摘要

Detection of highly ppm range hydrogen concentration in atmospheres contaminated with various volatile organic compounds is in demand for numerous applications. Different devices and techniques have been applied for the problems which are mostly based on utilization of hydrogen permeable membranes. Here, we have used a single generic metal oxide gas sensor for this task. No filter or membrane is utilized. The operating temperature of the sensor is modulated with a voltage waveform specifically designed for producing step-like temperature changes on the oxide pallet. By applying four different step-like temperature jumps, each of 1s duration, the sensor produces response patterns which are processed with common pattern recognition techniques. The technique was examined by its practical use for the ～10 ppm (volume) hydrogen measurement in a background containing ～1000 ppm ethanol. The analysis takes only 4s, and the obtained patterns are reproducible.