Hydrogen Sensor with a Thick Catalyst Layer Anchored on Polyimide Film

Abstract

Hydrogen sensors are important in a hydrogen-driven society to prevent explosions caused by hydrogen leaks into the atmosphere. In previous studies, resistive hydrogen sensors on polymer films have metal oxide nanostructures decorated with novel metals that enable good responses at room temperature. However, the in situ growth process of sensing nanostructures has the disadvantage of ineffective fabrication, particularly when preparing a thick catalyst layer to produce reliable readouts from the catalytic hydrogen combustion. This work presents a catalytic combustion hydrogen sensor with a thick catalyst layer anchored in a UV resin layer on polyimide film. Catalyst anchoring channels are made by UV imprinting with a glass mold. The sensor consists of a sensing electrode and a microheater, both made of Au within an area of 1.2 mm diameter. UV imprinting produces a UV resin layer of 27 µm thick and catalyst anchoring channels of 14 µm deep and 20–30 µm wide, which are filled with Pt/TiO₂ as a catalyst. The sensing response is 7.9% for 1% H₂ under ambient conditions, and the detection range is 0.1–3% H₂. The UV-resin microstructures can effectively retain a thick catalyst layer to enhance sensitivity, and their low thermal conductivity reduces heat loss.