Temperature balanced hydrogen sensor system with coupled palladium nanowires

A temperature compensated hydrogen sensor was designed and made capable of detecting H-2 within a broad range of 100-10.000 ppm while compensating instantaneously for large (+/- 25 degrees C) temperature variations. Two related operational constraints have been simultaneously addressed: (1) Selective, and sensitive detection under large temperature changes, (2) Fast warning at low and increasing H-2 levels. Accurate measurements of hydrogen concentrations were enabled by matching relevant time-constants. This was achieved with a microchip having two temperature coupled palladium nanowires. One of the H-2 sensitive Pd nanowires was directly exposed to hydrogen, whilst the other nanowire was used as a temperature sensor and as a reference. A drop forging technique was used to passivate the second Pd wire against H-2 sensing. Temperature effects could be substantially reduced with a digital signal processing algorithm. Measurements were done in a test chamber, enabling the hydrogen concentration to be controlled over short and long periods. An early response for H-2 sensing is attainable in the order of 600 milliseconds and an accurate value for the absolute hydrogen concentration can be obtained within 15s. (C) 2015 Elsevier B.V. All rights reserved.