Enhanced Hydrogen Gas Sensing Performance of Gold Nanoparticle Decorated Nitrogen-Doped ZnO Nanomaterials for Improved Sensitivity and Rapid Response

This study investigates the enhancement of hydrogen (H<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>) gas sensing in nitrogen-doped Zinc Oxide (ZnO) nanomaterials through the decoration of gold (Au) nanoparticles. ZnO nanoparticles were synthesized via a wet chemical method, doped with nitrogen at 0.5%, 1.0%, and 1.5% concentrations, and decorated with Au nanoparticles. Characterization using X-ray diffraction (XRD) revealed that the ZnO structure remained intact, with the addition of a peak corresponding to Au at 38.19°. Transmission electron microscopy (TEM) confirmed the uniform distribution of spherical Au nanoparticles on the ZnO surfaces. UV-Vis spectroscopy showed an enhanced absorption peak at 532 nm due to surface plasmon resonance. Photoluminescence (PL) spectra indicated reduced emission intensity, suggesting effective charge transfer between ZnO and Au. Gas sensing tests revealed that Au-decorated 1.0 wt. % N exhibited a maximum H<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas response of 89% at 200 °C, significantly higher than the 46% response of non-decorated 1.0 wt. % N. Additionally, the Au-decorated N sensors demonstrated a rapid response time of 10 sec and a recovery time of 15 sec. These results highlight the potential of Au-decorated N-doped nanomaterials as highly efficient H<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas sensors, combining enhanced sensitivity with fast response kinetics.