High Sensitivity Plasmonic Sensing of Hydrogen over a Broad Dynamic Range Using Catalytic Au-CeO2 Thin Film Nanocomposites.

Next-generation gas-sensor technologies are needed for diverse applications including environmental surveillance, occupational safety, and industrial process control. However, the dynamic range using existing sensors is often too narrow to meet demands. In this work, plasmonic films of Au-CeO2 that detect hydrogen with 0.38% and 60% lower and upper detection limits in an oxygen-free atmosphere experiment are demonstrated. The observed 15 nm peak shift was 4 times stronger versus other plasmonic H2 sensors. The proposed sensing mechanism that involves H2 dissociation by Auδ+ nanoparticles was validated using XPS, kinetics, and Arrhenius studies. Our understanding of this remarkable sensing behavior in oxygen-free conditions opens new horizons for packaging, art conservation, industrial process control, and other applications where conventional oxygen-dependent sensors lack broad dynamic range.