Author

Jonathan Rice

Date of Award

5-2014

Document Type

Thesis

Department

Environmental Resources Engineering

Thesis Advisor

Theodore A. Endreny

Abstract

An alternative energy source to petroleum is hydrogen fuel-cells, and better hydrogen sensors are needed to detect low hydrogen concentrations to make these fuel-cells safer. Pure palladium hydrogen sensors, based on networks of ultrasmall nanowires sputter-deposited on a filtration membrane have shown promising results, especially when alloyed with other metals or when layered with other metals. Unfortunately, even the best palladium-based hydrogen sensors still cannot distinguish hydrogen concentrations below 3% or at high operating temperatures, thus limiting the safety and application of the sensors. This study reports on new resistance based sensors of alternating nanowire network layers of pure palladium and titanium dioxide. These sensors show promise at sensing both low hydrogen concentrations, as low as 0.01%, and at sensing hydrogen at an operating temperature of 150 degrees Celsius; a step in the direction of sensors that work at temperatures approaching 1000 degrees Celsius. Although the titanium dioxide layers are not as sensitive to hydrogen as the palladium, they help to increase the durability and potential operating temperature of the sensor by providing additional adhesion and sensing properties.

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