High Sensitivity Plasmonic Sensing of Hydrogen over a Broad Dynamic Range Using Catalytic Au-CeO ₂ 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-CeO ₂ 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 H ₂ sensors. The proposed sensing mechanism that involves H ₂ dissociation by Au ^± 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.